I have a 1984 Trans Am with a Q-Jet carb. I was driving home from a cruise night when my "Choke" light came on. When I came to a stop the engine would not idle unless I held the gas pedal down slightly. The choke light now stays on and the engine does not seem to be running smoothly. This happened once before and it turned out to be a blown choke heater fuse. This time the fuse looked OK but I changed it just to be sure, but the Choke light remains on. Any ideas?

 

Choke light bulb grounds through the choke heater. The choke heater gets its power from the oil pressure switch on the back of the block. Without the choke heater functional the choke is likely staying atleast somewhat closed.

 

'You sure about that? That's not how it is on my '83. Why would '83 be different from '84?...

 

Is your alternator charging?...

 

I think TL is right, I seem to recall the choke heater relay being controlled by the alternator, such that in normal operation if the alternator isn't spinning & putting out power (usually meaning the engine is not presently running) that the choke won't be being heated on an engine that isn't running & warming up. When the alternator fails it of course acts as if the engine isn't running......

Bonus points; if the relay itself has failed, you CAN get a choke light and still have a functioning charging system, the alternator controls the relay, which controls the heater......

Now, I could be wrong, it's happened once or twice before (and, , , Sofa is usually right there to point it out to me, bless his heart )

Here is your 1984 wiring diagram showing the choke heater relay connected to the "Generator" at the lower left side of the diagram on the brown wire

 

They used a whole bunch of schemes for that circuit in various years.

However all that might be, the "Choke" light is ACTUALLY the "Alternator" light. For whyever, probably EPA regulations or some such, it was thought more important to warn the car's user that the choke wasn't working right, than that the battery wasn't getting charged. The reason for all this is that the charging circuit and the choke heater circuit are intertwined such that the choke heater won't get power (and therefore won't pull off) unless the alt is charging, which prevents the choke heater from getting heated if the key is on but the engine is not. And if the choke doesn't pull off, the car will be MASSIVELY rich, like black smoking rich, and obviously this is an emissions issue. Butt rather than tell you what's REALLY wrong ("I'm having a heart attack"), it tells you about some minor symptom ("my face is turning grey"). W/E.

So, first thing to check when the "Choke" light won't go off, is the alternator. About 99.999% of the time that's the problem. The other .001% of the time, it's some one of ALL OTHER possible causes. No need to even start thinking about those yet.

Start at the alternator. Use your digital multimeter to measure some voltages. What's the voltage between the Big Red Terminal on the back of alt and the case, when the car is running? What's the voltage across the battery terminals - the TERMINALS themselves, the physical parts of the battery itself, NOT the connectors, NOT the wires, NOT ANY OTHER parts - at the same time?

 

Thanks for responding. Will replace choke heater and go from there.

 

Thanks for your reply. Will have the alternator checked out and go from there.

 

Actually, no....

If you look at the schematic I provided, the "Choke" light receives it's ground through the choke heater itself, and receives it's +12V power from the 10A "C-H" fuse that supplies power to the brown wire. If the choke heater were to go electrically open, the choke light (ironically) would NOT illuminate when the choke relay was not engaged, as it would have no ground. The fact that your choke light IS illuminated means that the choke heater is fine, and the reason the choke light is on is that the relay's switched contacts are open. A no charge condition or a malfunctioned relay are the prime suspects here.





As Sofa said, get a voltmeter and put it across the battery terminals with the engine running. If you have 13.5 to 14ish volts, it's likely not the charging that's at issue. If it's anywhere in the 12 volt or less range, yeah it ain't charging. If you DO have 13.5 or better, your next check with the voltmeter will be across the two brown wires at the choke heater relay's connector. If you have the same 13.5 or better there that you had at the battery, then the relay itself is at fault.

 

Thanks to all that replied to this post. When I went to perform tests on the alternator, I came to the discovery of a missing alternator belt! Who'd a thunk it? Replaced the belt and all is good. Thanks again.

 

That'll keep it from reaching full output every time...

 

On the bright side, a lot cheaper fix. With my luck it's almost always the most expensive fix.

 

This problem often gets traced back to the wiring at the back of the Alternator. The Brown wire circuit terminal is either cruddy and doesn't make good contact or the wire is bad. While it could be caused by any number of reasons,.. that's where I'd look first.

* for anyone finding this thread in the future: This schematic is a bit more dedicated to the CHOKE and a lot easier to read due to the color coded diagrams; It's from an 85

 

Well while we're at it, John, can you show how the C/H fuse powers the fan relay on the VIN G cars?...

 

Sure: Here Ya' Go !

** Note: This is an 85 schematic for L69.

The schematic from 84 shop manual - for VIN '7'- shows there is no Fusible Link "F" before the cooling fan relay. 83 and 84 L69 might - or might not - have a Fusible link "F". The 84 Helm manual doesn't specify engine code 'G' anywhere and I think most engine code '7' schematics in that manual are related to L69 and NOT LU5 engines. Diagrams were probably just pulled from the 83 service manual and used in early 84 print shop manuals without correcting the VIN code. I can't remember if LU5 had an electric or clutch fan ?

 

I've got a question here;

The original poster of this thread had the "choke" light on. I've seen that light on some Fbodies with carbs, but in John's diagram the only light is shown as a "volts indicator" with a little picture of a battery. Am I to believe that car (1985 vin H & vin G) had a carb but didn't have the yellow choke light, but instead a red volts light? If this is true, if you have this information, will you post which applications had a carb but didn't have the choke light?

I just figure the more information available the better to help future readers who may or may not have the choke light

 

What the Heck ---> I've got a little timer to kill !!

This schematic is for an 85 'regular' Camaro analog cluster. It shows that the BLUE wire that feeds the CHOKE "indicator" light is circuit # 78 and it's splits into 2 paths.......



That's about the best I could find for the 'regular' Camaro thru that 85 HELM shop manual. However; I did find the 85 Berlinetta specific schematic for the same year and that one is a bit better detailed:



As you can see it too specifies that the BLUE wire is circuit #78 and the 2 paths it leads to are the choke heater and the choke heater relay. The dash wiring harnesses for each car are VERY different and it appears that the split in the BLUE circuit happens at - or near - the cluster itself in the 'regular' Camaro and at a specific breakout splice (S978) somewhere in the Berlinetta dash harness.

I checked the C100 schematic for the 85 and found that the BLUE wire leads thru Terminal "E6" on both the Berlinetta and the Coupe C100 for that year, so it's a safe bet that 84-87 cars all had the same circuit assignment for the Choke Heater wiring: AKA Circuit #78. ( in CARB cars ! ) I am going to assume (safe bet) that Firebird cars of the same vintage will also follow along with the same circuit assignment.

https://berlinetta.info/C100.htm

 

Thank You very much John!

When it comes to info on the choke light, the more the merrier

Back in the early 1990s I owned an 87 T/A with the 305 / carburetor and I'll be damned, I truly can't remember if it had a choke light or not......

My long ago first F Body;

 

Thanks, John...

 

Note that the "mystery split" has one arrow that looks like an "in" and one like an "out". They're most likely, one from the relay, and one to the choke heater. Find the parts of the schematic with those 2 things and see if that accounts for it.

I've never heard of any interconnection between the CH and the fan, except possibly the pink/blk circuit. Not that I've heard of everything, or that I remember even a small fraction of what I HAVE heard of, butt still... that wouldn't make the least bit of sense, functionally.

 

On circuit #78 there is an "in" (to the indicator bulb from Relay) and an "out" (to choke heater itself).

Choke Heater / Fan relay is responsible for providing POWER to the Choke Heater and to the cooling Fan relay on the BROWN wire; Circuit # 250 ( carb cars with electric fan )

PINK / BLACK wire is in no way related to the Choke Heater or Fan Relay,... it's a GAUGES fuse circuit to power various cluster functions.

** I wonder if some schematics show VOLTS as used for a simple indicator ( AKA: "dummy Light" ) cluster vs. CHOKE for gauge clusters ??? ( Just a quick GUESS; The schematic does specify volt 'indicator' and not volt Gauge ??!?

I'm always learning,........... and always glad to help !

 

Where is the throttle kicker relay located?
The reason I am asking this stuff is my Firebird did not come with an electric fan. I installed one from a '84 VIN G Camaro and wired it with an after-market relay and thermostat switch from Painless. It works fine, but I think I may have connected the relay power before the C-H fuse rather than after it, because when I pull the fuse, the fan still runs. I tapped into the brown alternator wire to switch the relay (not brown with a white stripe). It gets power only when the engine is running (obviously). The fan power goes through a circuit breaker, but I am not sure the relay power is fused...

 

REALLY...

LOOK AT the diagrams you yourself posted in post #17. In the first one (non-Berlinetta) pink/blk wire #39 goes from the GAGES (sic) fuse to cavity 2 of connector C1 to the cluster; inside the cluster it powers 3 things: voltmeter, fuel gauge, and "Choke" warning light. The other side of the "Choke" light then goes via cavity 3 of C1 to the blue circuit #78 with the "mystery split" in it, which was the one I was discussing.

The Berlinetta diagram is similar, except that the wire from the GAGES fuse to the "Choke" light is pink/wht, the circuit is #350, and 2 wires in that circuit from that same fuse go to the "digital cluster".

These do in fact differ greatly from the diagram you posted in post #13, which does indeed power the "Choke" light from the C/H fuse.

 

Yes - really. The gauges fuse doesn't power the Fan / Fan Relay or the Choke Heater. I then explained how those 2 things (the CH and the Fan) ARE related ( circuit #250, BROWN ) . If the PINK/Black wire was cut the Choke Heater will still work,.... & so will the Fan/Fan Relay.

Indicator or "warning" lights: All of them, & and all of the other gauges. ( AKA: "various cluster functions.") That's not what was being discussed. You asked about an "interconnection between the CH and the fan" and I thought I might be able to help. But your still confused,.... Sorry I couldn't help.

There is no "mystery split",....The factory splice is shown in the Berlinetta dash harness as "S978". The same split is shown as a 2 wire terminal at the cluster plug for the "regular" Camaro dash harness, (no "S978" splice with Coupe wiring.) Mystery solved.

The Throttle Kicker itself (manual calls it a "Idle Stop Solenoid") is mounted on the factory ECM controlled Carb and the Throttle kicker relay is mounted on the Driver side of the Relay Bracket on the engine firewall. (** Note Engine code '7' shown from 84 Shop manual; the V6 Throttle Kicker Relay for 84 and earlier carb V6 is shown on the pass side of the radiator support. ) Pretty sure all that wiring is run thru the independent ECM harness used from 82-87.

You'll have to check your own custom wiring to be sure,.. but the power supply IN to the Choke Heater fuse comes from the Column Ignition switch when in RUN. The same circuit ( ORANGE #300 ) also feeds power IN to the WDO power circuit breaker and the HTR-AC fuse.

 

"Better to remain silent and be thought a fool than to speak and remove all doubt."
– questionably attributed to Abraham Lincoln

Did you ACTUALLY go back and LOOK AT the diagrams you posted?

John, you are an intelligent and knowledgeable source of info on this forum. You have a VAST amount of knowledge and experience, and LOTS of resources like ... factory schematics. We're lucky to have such a one as you. Too bad you have to ACT LIKE AN IDIOT so much where I'm concerned. If you spent HALF AS MUCH time actually PAYING ATTENTION to what you're saying, and making sure it's RIGHT before you open your mouth (keyboard) and hit "post" and remove all doubt, instead of getting all wrapped up in trying to attack ME and making a EFFFFFFING FOOL out of yourself in the process, you'd be AHELLUVALOT MORE credible. As it is, ... you spoke, and removed all doubt.

Go back and LOOK AT the 2 diagrams YOU YOURSELF posted in YOUR post #17, particularly the 1st one, and explain CAREFULLY how the blue choke circuit wires don't get their power from the pink/blk circuit. Be sure to post up on here all about how IN THOSE DIAGRAMS "the gauges fuse doesn't power the Fan / Fan Relay or the Choke Heater". I'm forced to admit, after a 50-yr career as an electrical/electronic engineer myself, that your pronouncement BAFFLES me; it belongs in the Journal of Irreproducible Results.

FYI the 83 Helms manual for Camaro (yes I HAVE A COPY) doesn't have ONE SINGLE EFFFFFFING WORD about the L69, because it was published in late summer of 1982 when the 83 models were introduced, butt the L69 DIDN'T EXIST until about 9 months later, around March 1983. The manual unfortunately failed to include any "Features From The Future". 83 L69s got the "7" VIN code. Yes, I HAVE ONE. 84 L69s had "G" code. "7" was the LU5 code in 82 & 83. I have no idea (I didn't work for GM at the time) why they did what they did in 83 by re-using the same code for a different motor at the same time that the first one was still in production; butt as "They" say, It Is What It Is, now, 40-some years later.

Have a wonderful day! Fact-check yourself next time before making yourself look like a FOOL. No need for you to apologize, even though it would be the right thing for you to do; I'm long since over expecting any such, no matter how egregiously I've been involuntarily consigned to deserve one.

 

Part of the issue is how odd this system is, atleast today when it would be CPU driven, and also varies depending on the year and application.

However, I also don't know about the note that the pink/black circuit powers the choke circuit unless referring to just the lamp. The lamp and the choke heater/relay are two different circuits, that are tied into each other to make each function work correctly, but that Choke Warning lamp in the 1st diagram in post 17 that is powered by the pink/black wires cannot go on to power the choke heater or circuit from the other side of that lamp, or that lamp would never work. It's not being used like GM's trick to excite the alternator. Right?

From the diagrams posted in post 17, I thought those blue wires would be grounded when the engine is not running (alternator not outputting and can't ground the relay to open it from normally closed) with one end to the choke heater but using it as a ground (pass through) to illuminate the Choke warning lamp because the relay, the wiring, fuse, or the alternator are not in normal Run configuration.

 

I'm definitely no expert on the subject (hence all my questions), but the way it was explained to me a few years ago by Orangebird is that one side of the bulb gets 12v+ from the Gauges circuit and the other side gets 12v+ from the C/H circuit when operational, rendering the light OFF. When the CH circuit is not operational (such as key On with engine not running, Alt failure, or Choke heater relay failure or failed choke heater itself), that side of the bulb is grounded and therefore illuminated. This is what helped me to troubleshoot My choke light problem leading me to discover the the choke heater relay had been removed by a P.O. Again, I am ignorant here, but I am not seeing in the diagram as shown, how the Gauges circuit (pink wire) could possibly be powering the Choke heater or Fan relay. We all know it doesn't, but I think the drawing was being called into question, but in my dumbness, I am not seeing how it's wrong...

 

Exactly correct. One side of the bulb gets 12V from ... some fuse or other depending on the specific year model etc. of the car, and the other gets grounded by the voltage regulator inside the alternator if the alternator isn't charging which lights the light (12V on one side and ground on the other) and the light lights, or, if the alternator IS charging, it puts 12V on that side of the bulb TOO, in which case there's NO voltage ACROSS the bulb, so it stays dark.

The issue at hand is, in SOME cars, such as the ones John posted the diagram for in post #17, the 1st side of the bulb gets 12V from the GAGES (sic) fuse via the pink/blk circuit, butt in OTHERS such as for example my own 83, it gets the 12V from the C/H fuse via the brn circuit. John insisted, despite the diagram he himself posted, that the pink/blk circuit is NEVER involved with any of that. Ummmmm... sorry, not sorry.

All you have to do is LOOK AT the diagrams he posted in post #17. Note in the 1st one that the pink/blk wire #39 goes from the GAGES (sic) fuse to cavity 2 of connector C1 to the cluster; inside the cluster it powers 3 things: voltmeter, fuel gauge, and "Choke" warning light. The other side of the "Choke" light then goes via cavity 3 of C1 to the blue circuit #78, which connects to the C/H relay via one of the blue wires, and to the choke heater itself via the other. The coil of the choke heater relay is operated by the alternator such that if the alt isn't charging, the choke heater doesn't get 12V, the relay contacts that would send 12V to the choke heater on the blue wire are not made (remain open), and the light lights, by way of one side being hooked to 12V from whichever fuse, and the other side being grounded through the choke heater element which has a VERY low resistance compared to a light bulb such that it might as well be just another piece of wire as far as the bulb is concerned. Some cars, the light gets that upstream 12V power from the C/H fuse via a brn wire, and in others it gets it from the "GAGES" fuse via a pink/blk. Functionally it makes basically no difference which one the circuit gets its power from, when it's working right, since both of those circuits get THEIR power from the same contact of the ign sw. The ONLY time it matters, is when YOUR PARTICULAR car doesn't work right, and you have to troubleshoot it, and you're trying to trace the wiring or the fuses. Then, it would help greatly, to know clearly which fuse and what color wire is the high side of the bulb circuit. Which isn't the same for all cars.

It's really not that complicated, and CERTAINLY not "odd".

 

Exactly correct. ONE of those blue wires goes to the choke heater element, which is a VERY low resistance, and might as well be just another piece of wire as far as the bulb is concerned. Enough current can flow from whatever fuse, through the bulb and then via the blue wires through the heater element, to light the bulb if the relay isn't operated, butt it's far too little to heat the heater appreciably.

The 12V on the OPPOSITE side of the bulb, the one connected to the "other" wires, the "high" side for lack of a better description, comes from one of 2 circuits (fuses), depending on the year model etc.: the pink/blk "GAGES" circuit, or the brown "C/H" circuit. Both of those are supplied by the same contact of the ign sw, so there's essentially ZERO functional difference between them, as long as no fuses are blown. They both get the same 12V at the same times. (or not) AFAIK the relay contacts, which provide power to the choke heater itself via the blue wires, are supplied from the C/H fuse in ALL cars, regardless of which circuit the light bulb is powered from.

Then when the alt IS charging, the relay operates; and when its contact contacts, it puts 12V (from the C/H circuit as described) on the OTHER of those 2 blue wires, which simultaneously starts heating the choke heater, and turns off the bulb, since the bulb will then have 12V on BOTH sides. In order for the bulb to light it must have 12V on one side and ground on the other; it will not light if both sides are connected to the same voltage. Current can only flow from batt to gnd; it can't flow from batt to batt, or gnd to gnd.

 

Sure is when the Choke light is the indicator you get for a charging issue. Or having a Choke light period.

 

Dude:

YOU claimed you didn't understand how; "I've never heard of any interconnection between the CH and the fan, except possibly the pink/blk circuit. " and I tried to explain thru the BROWN wire,... That's it. You can throw anything else you want in the air and start an argument ( as you've done here ) about a Blue wire, Light Bulb, Alternator - WHATEVER - JUST to make an argument about it. I tried to explain what the "interconnection between the CH and the fan" was - just like I would for anyone else - and you really didn't seem to appreciate it: You didn't ask about the Choke and the Gauges,... didn't ask about the Fan and the warning lights, You asked about THE CH and the FAN; Your answer is:

Why toss out some crap around a "mystery split" in the wires ?? All I did was to mention they are in different places because it's a different harness and that alone gave you something else to ****-&-Moan about. I even agreed with you about PINK/Black in that it fed the cluster for the Indicators and various other functions and that too much for Ya,...... just more ammo for Your well-known keyboard troll antics.

If I had written " PINK / BLACK wire is in no way related connected to the Choke Heater or Fan Relay" would that have spared me the Vitriol ?? Bashing my credibility because I posted a couple schematics and you didn't like my answer to a question you posed to the group,.... Screw U Dude.

Take (maybe) Ol' Abe's advise and just stay quite next time you get the urge to be a pric.

 

Guys, two things here are obvious;

#1, it's obvious you both have a bunch of great Third Gen F body knowledge.

AND

#2, it's obvious you both have had enough negative dealings with each other in the past to not be able resolve your differences of opinion in any kind of gentlemanly fashion.

The thread deserves a proper resolution so as to BE a help to the future readers who search "why is my choke light on" , vs seeing you two choke each other over past bad blood.

 

Not really.

The only thing that's "odd" is the text on the bezel. The light is REALLY an alternator light, same as any other car before. Just, apparently the emissions ***** decided that alerting the driver to an emissions violation situation (choke not pulling off properly, therefore running EXTREMELY rich maybe even to the point of black smoke, therefore HEAVILY emitting hydrocarbons and CO) was more important than telling the owner what's ACTUALLY WRONG with the car, so they could go right to it and fix it. So, the light itself isn't "odd" at all; the "updated" labelling is merely confusing and misleading and useless.

I'm not sure when that started. I had a 78 and a 79 Z28, and both of those, seems like they had a light that said "Gen" or some such or maybe was a little battery icon. Proper labelling of some kind, in any case. I knew people who had 80 & 81s, and test-drove 82s when they came out, but I don't remember how any of their lights was labelled. Maybe somebody on here with a 82 can tell us what their light has on it. My 83 says "Choke". So sometime between 79 and 83 they must have taken that left turn.

 

Yes, really. Saying a light that is mislabeled isn't odd is, well, odd itself. It's fine if you don't agree.

Yes, the light will (should) light if the charging system is not working but it will also come on for other reasons not related to the Alternator. Like broken wiring, missing Heater relay or contacts broken, Fuse blown.

 

It's not past bad blood,... I don't hold grudges,.....this started 2 days ago @ 6:42pm.

Read up to post 24 and LMK what I did that was in ANY way out of line. What exactly did I post that was deserving of deformation and insult ??

Sofakingdumb replies in #25 with offensive comments about me personally and challenging my credibility. WHY ??? Where's did I ever "attack" anyone ?? WTH is he even talking about ???? He asked a specific question & I answered it correctly,.... No insults, nothing derogatory, not even sarcasm ! It's not even like I was wrong about the circuit he asked about !

No Matter how I look at it the PINK/Black wire has nothing to do with the CHOKE Heater / FAN fuse; & that's precisely what he asked about. He coulda'/shoulda' just wrote,... 'Hey thanx, I didn't notice that.', But instead he takes things out of context, makes a straw-man argument, (John insisted, despite the diagram he himself posted, that the pink/blk circuit is NEVER involved with any of that.) claims he was attacked (makes himself a victim) then begs for a apology; Gaslight much ??? I didn't challenge anything he wrote and certainly didn't throw around personal insults, make straw-man arguments or claim to be a victim of a non-existing attack. Simply Pathetic.
`
I don't have much and I will defend the reputation I've spent a generation establishing. I've had MANY "spirited debates" with MANY other members here over the years; that's not what happened here,.... not even close. Am I'm wrong for defending myself against this kind of behavior ? I very much thought I was helping the topic Choke light stays on by posting a few schematics, diagrams and answering questions to the best of my ability,..... In return I get insulted, defamed and discredited. This is not past bad blood, the blood is still wet ---> & I will stand up for myself and defend the reputation I've worked so hard to build.

Orange: Your right and I agree, enough negative dealings,.... I've placed him on my ignore list to avoid this kind of nonsense in the future. Maybe by ignoring the problem it will just go away..

 

I agree completely, that the "Choke" labelling is STUUUUUUPID. It's the labelling that's "odd" not the light itself.

Maybe the reason some cars have their light wired to the pink/blk "gages" circuit instead of the brown "C/H" one is precisely that: if the C/H fuse powers the light, then if it blows, not only will the choke heater not heat, but also the light will not light. I'll have to go back and study the schematic to see if the light will come on in that situation as long as the alt is working.

 

Anyways, @John in RI I noticed one of your diagrams for the Berlinetta it had a note "OK To Go" Light. Is that an actual light/message on the Berlinetta, perhaps their digital cluster?

Between a Choke Lamp and a "OK To Go" light (if the diagram is accurate), it sure is odd (to me) in part because other non-GM products from this period that I've owned had no such indicators.

 

Yup,.. The OK to GO light is on the bottom/right of the cluster.

The Berlinetta cluster has a section called a "System Monitor" and all 8 telltale indicators get lit-up as a bulb test when key is turned to RUN. If the key is left in RUN than a couple of the indicators will go out (as long as three isn't a problem) but a couple will stay active till the car is started. ( Choke, Oil pressure for example. ) Once the car is started & running the cluster begins it's self-check again & the indicators go out 1 by 1 in a specific sequence. Once the 7 indicators pass that check,.... the cluster lights up the green "OK to GO" light briefly.


Really kinda' neat to watch when it's all working as it should !