Hello! I have an 89 RS 305 TBI Auto trans. My main issue is a no start condition (no response at all from the starter even though its been tested and is good). But I cant tackle that yet because the battery is constantly dead due to the interior lights staying on. The driver side door trigger seems to be in tact and working (dont really know how to test it) but the passenger side one is missing. After removing passenger kick panel I was able to fish out a single white wire that was missing a connection and I am assuming it went to the passenger door trigger. This doesnt make sense though, how are the lights running of the circuit isnt complete due to the missing passenger door trigger? What else could cause the interior lights to be on besides the two door triggers? Id drive it off a cliff but I cant get it to start anyways.

 

Rotate your headlight switch **** about 30° to the right.

 

Four years later and @sofakingdom is still here to make me look stupid. I didn't realize that was a thing. Always just assumed my headlight **** was broken. Can you fix my no start issue like this as well? lol.

 

I'm sorry, but Sofa's response is funny as heck.

Dome light will light up when a ground path is provided to the chassis. The door switch is just one of several possible ground paths. You have a problem where one of the ground paths is active and won't go away. I can't remember all the different ground pathways, would need to see a GM wiring schematic to figure it out.

In the interim, you can remove the light bulb and maybe it will stop draining the battery.

 

​​​​​​​Yup, always has been. Goes back as far as I can remember which is well back into the 1950s. Just yerbasic manual control for the dome light.

Maybe. Depends on why it's not starting in the first place. First things first. Which is it: a no-crank, or a crank-but-no-run?

 

No crank. Back a few years ago when I was driving it consistently it would crank just fine until the car was hot. Wasn't really an issue because it would get me where I need to go and then would not start for 30min to an hour. No slow cranking either. It would either crank at full speed or not at all. The starter has been tested and is in good condition and is also heat wrapped. There were two red wires going to the starter that used to have fusible links but they were both damaged and exposed when I bought the car. Both wires have been replaced but instead of fusible links they have in line fuses at 30A which could be my issue but I am unsure because they have not blown, and a shop looked at it and said it might be fine though they have guided me wrong in the past. I have a multimeter and willing to try anything, just don't know what I am looking for. Now years later its just not starting. Could have to do with the weaker battery, but I feel it should still crank slowly or click a bunch of times at the bare minimum but I get nothing. I know it is not VATS either as the security light turns off in the car.

 

When you turn the key to Start but it doesn't crank, what is the voltage between the purple wire terminal of the starter solenoid (the "S" terminal) and the block, when your assistant tries to crank it?

It might help to see if the rest of the car also stops working at this time; like, turn on the headlights, and see what happens to them during a malfunction. But we'll get to that.

Note that this needs to be measured while it's in the failed, no-crank state. Since it's intermittent, checking it when it's working, is worthless. It needs to be captured WHILE IT'S IN THE ACT OF SCREWING UP. Very important: WHILE IT'S IN THE ACT OF SCREWING UP.

Measure that voltage and get back to us. We'll go from there.

 

I was going to test this today but the battery is dead and I believe the shop may have sold me a bad battery. I couldnt charge the brand new battery past 9V. I took it completely out of the car and charged it and put a multimeter to it once I turned the charger off and the battery drops from 9V to 1V in a matter of minutes. Am I an idiot or do I have a bad battery?

 

If it won't charge, it's bad, for whatever reason. That would definitely cause a no-crank. Might want to leave the charger on it overnight in case it's just drained completely flat but might revive.

 

Got a new battery. Pain in the ***. Got it to replicate the issue. Reading 7.04V to the terminal with the purple wire while cranking (while holding it down it would slowly go up to the 7.2V range). Been curious to see what the Voltage is like when it does work but I haven't been able to get it to work. I imagine 7V is not good.

 

No; not adequate.

Assuming that there's 13.x volts or so at the batt, then there's voltage drop in a wire or connection or component somewhere. Might be a good idea to check the batt voltage first while your assistant turns the key; then if that's OK, start probing everywhere downstream of that, toward the solenoid. Power has to go through a fusible link, then to a Big Red Wire, then through C100, then to a splice in the harness, then to the ign sw; all those wires are red. Then from the ign sw, a yellow wire to either the neutral safety sw if it's an auto or the clutch safety sw if it's a stick; then a purple wire to C100, through C100, and the purple wire continues to the solenoid. Easiest places to check first will be the NSS or CSS, which are also among the likely culprits.

 

Thanks for the help. I pulled the center console cover and messed with the neutral safety switch. Wish I knew a good way to test it but its probably worth replacing. Does it ground itself to the bracket? Might have cooked it a bit. A small puff of smoke from it once I got the car started by messing with it a bit but I didnt have it completely bolted down. Whoops. Might be worth replacing anyways. The kickdown cable for the tranny needs major adjustments so when I shift I always go through 1st and 2nd manually so I might have put some extra wear and tear on it causing it to go bad. But im still concerned on why it would show 7V at the starter. I feel like it would be 12V if in park and nothing otherwise but I guess if the part could be bad or misadjusted and is in an in between state it might show less voltage. Could I use the multimeter on one of the wires leading to the Neutral Safety Switch? See if im getting 12V in and 7V out somehow?

 

Ground isn't involved in that circuit. Doesn't matter whether it's grounded or not, as long as it's bolted down so the shift lever can move it.

If a puff of smoke came out of it, it's ... smoked. As we all know, everything electric or electronic works on the basis of smoke; as long as the smoke stays inside, it might work, but if the smoke gets let out, it usually won't work anymore.

Reason it shows 7V at the starter is, the switch might be bad. That's the kind of thing we're looking for here.

Yes. That's exactly what you can do. Ideally there should be 12V on both the yellow and purple wires when the car is in P or N and you turn the key to Start. Won't be any voltage on any of it if you're not trying to start the car. But if you see like 12V on the yellow wire and 7V on the purple, then that means the sw is bad.

 

Bought a new one given this one gave a puff of smoke even though after messing with it im getting the car to start. Going to put it in as soon as the part comes in tomorrow. In the meantime, I tested the old one directly off the car battery and it seems to give the right voltage in P and N but maybe it just needed to knock some of the dust out of it. The harness leading into the NSS is giving me 12 on crank so whatever it is its down the line from there. Either way I get to check it off the list tomorrow if I can get it to not start again.

 

Car hasn't given me any issues today with the NSS replaced. Time is the real test though so I am going to give it a few days driving and come back with an update. Thank you for all of the help @sofakingdom .

 

So it didn't fix the issue. So what could be next? Is the starter relay before or after the NSS? Seems like I am getting 12V to the NSS so it would probably be after?

 

Probably.

If there's 12V on the purple wire at the NSS while it's screwing up, then the problem is downstream of that. As said, the purple wire goes to C100, then to the solenoid; so C100 would be the next most likely culprit.

 

Do you know where this C100 is located at? Not super familiar with this stuff but it sounds like a harness? I am seeing that there are several components stemming from this such as most if not all of the instrument panel (which all read lower than normal while driving). Temp is below 220, voltage sits at 8/10 and fluctuates a little and oil pressure sits right on the lower red line at idle speed. Also is this something easily replaceable/repairable?

 

In fact, I do. It's the big connector that goes through the firewall right below the brake booster.

Yeah, all of it. So yeah, pretty much the entire car goes through that connector.

Hard to say. Brain surgery is easy (or at least, less difficult) to a brain surgeon; butt I doubt you'd want me rattling around inside your skull with a scalpel. Car electricity on the other hand, is just ... car electricity ... and as such, is one of the simplest electrical systems there is, and since there's like a billion of em in the world created by every society, ethnicity, etc., I'd say it's pretty easy. Hardest part is just getting to stuff. As simple and uncomplicated as it is, after all practically everything in it is just battery and ground, understanding it is about as no-brainer as anything can be. Which is probably why I'm so comfortable with it, since I have no brain.

 

So I pulled out the connector and it looks incredibly dirty due to what I think is 30 year old dielectric grease. Its caked on all of the prongs which I think need to be clean to provide a good connection. Ill give it a good clean. Does the C100 feed power into the cabin and then back out to the starter once its gone through the Starter Relay and NSS? Id like to hook up power and then test the prongs coming from the cabin while cranking if thats a possibility. Dont know if I need to feed power through a prong in the C100 as well to get a reading back out, or if it goes in a different way.




.

 

Except for the terminals that are green with corrosion, that's what it looked like brand-new. The stuff the factory used, looked like tar. No idea what it was or where to get it. There's other things you can use to replace it though. Bulb grease works pretty good if you get it in bulk.

Of course, how else could batt power possibly get from the batt to the ign sw, and then back out to a place under the hood? Gotta pass through the firewall both ways SOMEHOW.

You'll find that there are 2. If you take off the shroud and look at the wires, you'll see 2 Big Red ones. Each of them feeds power to about half of the car. In fact there are feeds from both of them that go to the ign sw, and ultimately power things that are switched by it. You'll also see the purple wire. Might want to concentrate your efforts on that one, and its contacts, first.

The harness has 2 parts. The smaller part is specific to the chassis; has things like headlights, turn signals, horn, etc. in it. In a word, things that don't touch the engine, and are the same in every chassis no matter what options it has. The larger part has the 2 batt feeds (since their exact details varies according to which engine is equipped), the gauges, starter, etc. in it. That whole harness is delivered from the engine plant to the vehicle assy plant already installed to the engine, and is plugged into the car at the assy plant. Oddly enough the wipers are in the engine side. The batt feeds are 2 of the big fat wide terminals. Pretty sure the starter is a big one too buitt I'm not sure. Butt you'll see all that when you pop the shroud off the back. All the ECM wires in your car are in a totally separate harness that goes through the windshield cowl at the pass side kick panel and as such are discrete from the "engine".

 

With the harness disconnected, I ran power to the cowl from the harness with one wire connected to the power terminal (A4) and upon crank I am receiving 12V from B4 on the cowl. I then ran a wire from B4 on the cowl to the appropriate terminal on the harness (B4) and then I cranked it again, and this time I am receiving 7V to B4 at both the harness side and cowl side. If I unplug the wire again I am reading 12V from the cowl. Coming from the C100 to the starter, is there anything else power runs through before it gets to the starter or is this the last wire? I feel like I should have my aha moment here but I am still quite confused. I feel like voltage would drop after the the bad part of the connection and not before, but maybe it just reads the same voltage across the entire connection? Will it read 12V if there is no load in the circuit/not completed circuit? regardless of if there is issues with it?

 

The voltage changes when you add the load of the solenoid because there's a bad connection somewhere in the chain.

I'm not sure how this is hard to understand. There are few things about a car that are simpler than the electrical system. It's just not that hard.

Think of electricity as like water, and wiring & devices as like plumbing. Voltage then, is like pressure (the "push" that makes electricity move) and current is like flow (the actual motion of electrons). A switch is like a valve that only has 2 positions, open & closed. Wires are pipes. Connections are like fittings that join pipes. Loads, like starter solenoids and headlights and whatever else, are like openings to the outside world that allow water to flow out.

OK: if you had a plumbing system and were trying to fill a bucket from an orifice at teh end of a pipe, but the bucket filled too slowly, what would you look at? That's EXACTLY like what's going on here: you're trying to get current to flow into a load, the solenoid; but the system can't deliver enough electrons. In a perfect world, every wire, switch, connection, etc. would offer no resistance whatsoever to current flow; butt in reality, each one does. Working properly, those resistances aren't enough to keep the flow that reaches the solenoid from being adequate. Butt, in your case, there IS a high resistance to the flow of current, SOMEWHERE. Just like, in your plumbing system trying to fill the bucket, if there was a pipe fitting somewhere that has a blockage.

So, if it was a plumbing system, you might use a pressure gauge (voltmeter) to look for the problem. So you put it on the pipe right before the orifice, with the orifice blocked (not flowing) while NOT trying to fill the bucket yet. It reads 60 psi - NORMAL. Have you REALLY learned anything? NO. What happens when you unblock the orifice? Let's say, the pressure at that point drops to 10 psi. WHY? It's because of the RESISTANCE - BLOCKAGE - somewhere upstream. So, you track back through the plumbing system, and at each point you can test, the pressure is 60 psi with the orifice CLOSED and 10 psi with it OPEN; until you suddenly come to some ancient black-iron fitting that looks like it's been there since the Revolutionary War, and voilà! the pressure UPSTREAM of that fitting is found to be 60 psi with the orifice (load) CLOSED and 58 psi with it OPEN!!! What's the bad part? What's bad about it? What would cause a pipe fitting to have a 48 psi pressure drop from one side to the other when there's some water trying to FLOW through it?

Your car is EXACTLY like this. You have valves (switches) and fittings (C100 and so on) and pipes (wires) located here and there along a multi-piece path that act just like plumbing parts. There's a small amount of resistance in it when it's working right, such that the voltage (pressure) stays nearly the same throughout; butt yours is defective, such that there's a YYYYYUUUUUUUJJJJJJJE resistance somewhere that's not supposed to be there. There IS one extra complication, which is, sometimes there's no extra resistance (car starts right up), but sometimes there is. Electrical things can do that, ESPECIALLY moving parts like switches. Connections can also have intermittents like that., butt wires rarely do, except at their ends (connections) or if they're physically broken.

THAT'S what your problem is. SOMEWHERE in your car there's a bad connection of some kind, like the crusty plumbing fitting, that acts as a resistance to FLOW. You can't find it by measuring PRESSURE unless there's FLOW going on, and even THAT won't find it, unless you observe it while it's in the "fail" mode. It'll look fine when it's working right. Which is why when you disconnect the solenoid and eliminate the FLOW of the current, the voltage doesn't change; but when the FLOW is active (solenoid is hooked up), the RESISTANCE in whatever the bad part is, reduces the voltage (pressure), sometimes.

It's so simple. Eeeeeeezzzzzzzzzy. The only hard part about it is, accessing each of those connections, physically. Kind of like, if the crusty fitting, was located inside a concrete block wall, and you had to tear down the wall to get at it. Eeeeeeezzzzzzzzzy in concept, maybe not so much to get at. Butt just not that hard to understand. Don't make it any harder than it has to be.

From your description it sounds like C100 isn't the problem. Put it back together and leave it alone. The problem is farther upstream (along the path from the batt, through C100 into the cabin, to the ign sw, to the NSS, back to C100).

 

Ah I see. So reading 12V means nothing if the circuit isnt closed. Once its closed its fair game. So When I was reading voltage at the NSS it was with the circuit open and not completed. So I guess I should go back and try to measure this again but with the circuit completed. And if its not there go back to the Starter Relay? If the circuit is closed though and im reading 12V somewhere then the issue is after, and if im reading 7V its before?

 

Right.

With the whole system completely put back together, and with it in its "failed" state (you're turning the key butt the starter doesn't engage), measure the voltage at each accessible point. You should see, say, 13.2 at the batt terminals; 13.1 at the C100 terminal that ends up going to the part of the ign sw that feeds the solenoid; 13.0 at the ign sw; 12.9 at the yellow wire at the NSS; 12.8 at the NSS purple wire; 12.7 at the purple wire on the cabin side of C100; 12.6 at the underhood side; and 12.5 at the solenoid. Or some similar pattern of very small voltage drops at each part, until/unless you locate the bad one, at which point the voltage will be 12.x on its gozinta, and 7 on its cumzotta.

I don't think your car has a starter relay butt if you have a diagram that says it does, that's another point you can measure at, and should see some similar tiny voltage drop.

All this of course, while everything is connected, and you're probing the point in question while your assistant turns the key (unless you can use alligator clip leads or something to free up your hands), and the system is in the "failed" state. You DON'T want to disturb the connections because if you do, they might suddenly and for no reason you can perceive, spontaneously change from "failed" to "good"; and at that point you no longer can troubleshoot anything unless you spot other evidence like burned parts, corrosion, or the "magic smoke" escaping. Rather, it will commence working right, and will SURELY fail again later, right when it's most inconvenient.

SOMEWHERE the voltage will change from 12.xx or whatever, to 7 or whatever. Whatever part makes that happen, is the bad one.

 

Here is a picture of what I think is the starter enable relay.

On crank I am getting 10.4V to all wires except the small green on is getting 1V in the starter enable relay. Although this is low im assuming im getting the same in as I am out so I dont think its the relay but maybe before the relay? Its reading 9.8V before and after the NSS, and 7V at the C100. Im at a loss now.
I don’t know what else to check unless someone has a wiring diagram for an 89’ 5.0 TBI

 

Even on power ive run directly from the battery into the cowl on the C100 I get around 12.7V (constant) into the cowl. 10.4V into the starter relay, 10.2V out, 9.8V into the NSS 9.6V out. 8.7V back at the cowl and 8.1V on harness side (wire ran from cowl back to harness for cranking). Seems like a general loss of voltage all around.

 

Is that while trying to start it, but it won't start?

 

If youre asking if I checked the voltage from the battery to the A4 terminal while in the act of cranking, no but im getting good power into the cowl and I was able to get it to both start and not start (very small differences in voltage during both). I imagine the voltage to the starter is right on the border of being enough voltage to engage the starter.

 

So, not really a valid test, in this context.

The batt itself, batt cables, fusible links, etc. can all be potential culprits in this. So, for example, the batt was 12.7V resting, but dropped to 11.3 or something while attempting to crank, then the rest of those voltage drops don't look near as serious anymore.

It's like people asking "how much will these springs lower my car". Well, we can't answer that; not least because, "lower" is a COMPARATIVE word, that depends on "lowering FROM WHAT". If your old stock springs sag enough, "lowering" springs might even RAISE your car. To evaluate a DIFFERENCE, you have to know not only the "end product", but also the starting point. "Voltage drop" is much the same: knowing what the voltage is after it's already been dropped, butt not knowing what it was to start out with, doesn't tell you what you need to know.

After all this, it's not impossible that all you need is a new batt; and then, the voltage reaching the solenoid might be 10V or more, and PLENTY to make it work reliably. Until it's all measured, no way to know. It all stays a guess.

 

12.8V Constant on the harness, no load. 10.4V under load from cranking. So it has to be in the wire from the battery to the C100? Checked for any signs of damage and did see that the outer plastic casing of the wire was a little melted from the headers, but the wire itself has a little plastic residue on it but no visible damage. Still, probably should be replaced.

 

Would replacing this wire cover the fusible link as well? And where does this wire end at? Im struggling to find a diagram for the 89’ RS 305 TBI.

 

Possibly so, yes.

If it's a Big Red Wire, and/or one of the fusible links that feed them, it starts at the big terminal on the starter that the batt cable goes to (for all practical electrical purposes, the batt + terminal) and ends at C100. Only exception would be, the Big Red Wire that feeds the blower motor high speed. That one goes from a splice somewhere in between those 2 points, and goes back over toward the pass side, to a connector above the right valve cover. Butt that one isn't involved in the issue at hand, so even though that connector is almost certainly burnt to ashes, it's not part of a starting problem. Only a blower high speed problem.

Doesn't matter that it's a 89 305 TBI, specifically. Doesn't even matter much that it's a Camaro. It's a GM. They're all wired largely the same in that area, in years anywhere near that. Very generic.

Not really. That's completely harmless, except for being a little ugly. More likely, you'd just end up creating more problems than you solve, by messing with it. Just wrap the tubing with some good electrical tape such as 3M 33+, and secure it away from the exhaust.

​​​​​​​I'd be more inclined to suspect the fusible link, down at the starter; it acts like a giant fuse, to protect the Big Red Wire from starting a fire in case of a short. Those, the insulation they used seems to shrink and crumble with age, and expose the conductors inside, which corrode, thereby becoming less conductive (more resistive). Sometimes they even short out to the little metal tube they go through down there and blow themselves. Yours obviously hasn't done that yet, butt it might be corroded enough, or have enough strands broken, that that's where the voltage drop you're seeing, is coming from. https://shop.advanceautoparts.com/p/...5623/5013097-p Wouldn't hurt to unleash a preemptive nuclear first strike against those. Also wouldn't hurt to use a yellow uninsulated butt splice, solder it after crimping, and cover with some serious heavy-duty heat shrink w adhesive inside it, such as . I wouldn't trust the thin little weenie crap they sell at parts stores for this.

 

I see. So I talked about those earlier, but they actually went bad a while ago. There were two fusible links I believe going to the large terminal on the starter, and they were both corroded and had exposed wire. I replaced them with in line 30A fuses and quick splices which im guessing is where the problem lies - Shitty replacement when I was a teenager. So this wire runs from the battery to the starter, then to the C100 where it does all of the validity checks before going back to the S terminal on the starter. Does this mean the entire car or at least alot of the stuff inside is under powered? lol. Also, im assuming based on the link you sent me ill need 14 gauge fusible link wire?

 

I went ahead and replaced the two with fusible link but nothing has changed. I am reading low voltage at the starter. I am only reading 10.6V to the main terminal (not S terminal) on the starter when im cranking (12.8V constant) but then I went ahead and read it from the battery at crank with the multimeter on the posts - 10.6V there as well. What? I know the battery isnt bad, its brand new and showing 12.8V constant. I thought I would get 12.8V under load as well and the problem would come after but I am getting low voltage under load at the very beginning. There were 4 fusible links to the starter and the positive battery wire. Since I am getting the 10.6V from the battery and I am reading the same at the Starter Relay, then my issue seems to mostly happen somewhere under the dash, where from the C100 heading to the starter its only reading about 8.5ish Volts. Seems like at this point I can only hope for making some part of the circuit more efficient. Upon further inspection, or boredom I guess, the wire heading from the NSS to the C100 gets pretty warm, not crazy hot but a little hot under load while all of the other wires seem to be just fine. Maybe its somewhere in the firewall where the wire connects to the C100 again?

 

Voltmeter says otherwise. They don't lie. BELIEVE them. That's what they're for.

Sounds like that's where your problem is. Kinda hard to get 12V ANYWHERE if there's only 10.x coming out of the batt. Switches, connectors, plugs, splices, wires, etc. can only DROP voltage; can't somehow GROW it. If it's weeeeeeek coming out of the batt, it's just gonna get weeeeeeeeker all the way along the line. Impossible (in this pitiful universe anyway) for it to work any other way.

THIMK for a minute about what comes next. Assume the batt drops from 12.x volts to 10.x volts just from applying the solenoid load (25 - 30 amps or so). What do you think is gonna happen in case the solenoid works, and it successfully hooks up a starter that draws 200 amps? Doesn't stand a chance. Gotta get the batt sorted out before you can go any further.

Try charging it up first. Overnight with a trickle charger at 5 amps or so.

No there's nothing wrong with that wire. All the wires are in series; the same current is going through all of them; that one might be a smaller gauge or something. Some connection somewhere can't cause a whole wire somewhere else to get hot. There's not a problem there.