Xophertony

So i got a PM from a guy asking me how I did my 140MPH guage swap. turns out he has "idiot lights". i was about 3/4ths of the way through the response when i thought "hey everyone might want to know all this, so i finished it up and re-wrote it more "tech article" style. but there are a few blanks..

XOPHERTONY'S Guide to Swapping a 140MPH Guage Cluster Into Your 85MPH/120MPH Guage cluster or "Idiot Light" cluster Equiped Firebird.
when I started out I allready had the "rally Guages" oil, coolant etc.. my speedo was only 85MPH. I pulled the two speedo's apart and swapped just the faceplate and circuit board out. this way I could retain my odomiter. if you allready have "ralley Guages" this is an option for you, i would recomend just swapping your odomiter gears into the new cluster. anyway..

FIREBIRD INSTRUCTIONS
1. remove lower "under dash" pannle from drivers side dash. should be little 9/16" / 8MM screws. also remove the next one. may hold your vent controls if you have no AC

2. Remove the two 15MM bolts that hold the steering column to the dash. this will allow it to hang down just a bit. if you have a tilt coulum it is possable to get the guage cluster out without doing this, but I broke my clear lense doing it so I would realy recomend dropping the colum a little, it sounds worse then it is.

3. remove cluster trim. on my 86 (might be different on pre-86) more 8MM screws. 4-6 along the bottom (under the dash buttons) and a few along the top tucked under the dash pad. you do not need to remove the dashpad.

4. now you should be able to see the cluster. there should be some screws retaining it. pull those and pull the cluster toward you. there will be one or two plugs going into the back of it, unplug them.

5A. if you had full guages before: now plug them back in to your new cluster and screw the guage cluster back in. go for a test drive. does everything work? yay, put it all abck together and enjoy.

5B. if you had "idiot lights" proceed to underhood instructions

CAMARO INSTRUCTIONS

1. remove lower "under dash" pannel from drivers side dash. should be little 9/16" / 8MM screws. remove the one above that, it may hold your vent controls if you have no AC

2.remove the T-10 Torx Bits from the front of the instrument panel.
Then, pull the two 10mm nuts located next to Service Engine Soon bulb and Fasten Seatbelts bulb.

3.you now should be able to squeeze your hands behind the guage cluster. there will be one or two plugs going into the back of the guage cluster, unplug them.

4. There is a black retaining clip holding the speedo cable to the cluster. It is diamond shaped. Just push that clip towards the cluster and hold it. The speedo cable should pull right out the back.

5. if you had "idiot lights" proceed to underhood instructions

UNDERHOOD INSTRUCTIONS


6. you need to replace the sending units for your collant temp and oil pressure. before you just had idiot lights, they were not set up for acurate reading.

6A. coolant tempature sender. differences between models.
V6CARS - front of intake manafold on left. buy the new one and use it to compare to old one as there are a few sensors here.

V8CARS - it is on the passanger or drivers side cylander head. there will be two sensors, one for fan and one for ECM/Guages. to test ground one and see if the fan comes on, if not, that is the one.
it may also be on the "top center" of the engine as my service manual states. so wherever you find it.

6B. oil pressure. there are some differences between modles here.
PRE1989 V8 CARS - right now your pre 1989 car reads from the sensor below the distributor, replace that with the newer one and be done, or re-run the wire down to the oilfilter area, and replace your oil-pressure switch with the 1989+ one and use that (in 89 they used the 3 wire switch and used it for oil pressure reading as well, saves space). plug old sensor hole.

89+ V8 CARS - i don't know that you could get idiot lights this late in the game, but if you have them, replace the oil pressure switch/sending unit. it is near the oil filter.

V6 CARS - The Chilton repair guide shows the oil pressure sending unit on the drivers side of the engine. pics are on pages 4-29 and 3-7. do not confuse this with the fan temp sending unit which is on the rear passanger side of the block.

7. if you are working on a 1986 or newer Firebird you should be fine for VSS wires. if you have a PRE1986 firebird you have a cable driven speedo you need to read THIS tech article to learn how to swap in a VSS and all other wiring for it. if you have a Camaro you are good to go.

8. installation is reverse of removal.

open a relaxing beverage of choice..



NOTE: the camaro instructions were, essentially ripped off from the tech article linked below. i have never done this on a camaro so i just plagiarized it.

musclecarfan87

I've searched all over the boards to find an article on the guages.....so finally I just asked Xophertony....

Thanks man, I appreciate it! I'm gonna probably start my swap later this week...or possibly tommorrow, weather allowing....

Xophertony

your welcome. glad to help.

Bad-Newz

Can anybody explain what exactly are "IDOIT LIGHTS"?

musclecarfan87

Those almost useless little lights that come on that tell you "service engine soon" or tell you your oil pressure is low, instead of having actual guages. In my case, I have an 86 Firebird with the 2.8L. I have a 85mph speedo, then a gas guage. Beside that (in place of guages) I have two rows of circular lights (my "idiot lights"). I hate not knowing what my engine is doing, bc when they come on it means something's already gone wrong. With guages, I can tell something's not right BEFORE its too late. Hopefully that helps some (or understood what I meant at least).

firstfirebird

iTrader: (3)

The SES light is not an "idiot" light as it actually is useful, especially for those that don't have computer diagnostic equipment.

musclecarfan87

True. I stand corrected.

Bad-Newz

OOOHHH. Thanx for clearing that up for me. I was wondering what that meant.

musclecarfan87

The Chilton repair guide shows the oil pressure sending unit on the drivers side of the engine on the 1986 2.8L engine. pics are on pages 4-29 and 3-7. Just thought I'd add that.

Xophertony

thanks red, added that to the original post.

nks06

will this work for an 87 camaro too?

Xophertony

yes. with one exeption. the removal and re-installation of your cluster is physically more difficult. but there is a tech article on the main page describing it in detail.

https://www.thirdgen.org/gauges

i'll add this to the main instructions.

musclecarfan87

No prob. Glad to help.

nks06

thanks a lot

oldschool

Those thinking of trying to swap a factory gauge cluster into a Firebird originally equiped with warning lights will have to repin the two connectors on the dash harness for the cluster. The wires are in different positions for the gauge and non gauge clusters. GM used two different instrument panel harnesses on the Firebirds: one for gauge cluster cars, one for idiot light cars. All you will do is blow fuses if you just switch clusters. Also the idiot light cars use the charging light to activate the alternator so it starts charging the battery. Camaro guys have it much easier with this one.

firstfirebird

iTrader: (3)

Isn't that easily fixed by using a 10ohm resistor in series where the light would normally be?

musclecarfan87

Hmmm...haven't started my swap yet....what exactly will I need to do it then? I've already planned to buy the coolant temp sensor, and oil pressure sending unit....do I need to add to that shopping list(such as extra wire, different connectors, etc)? This is my first guage swap, so I don't know too much about doing it....

thx

oldschool

For a Firebird warning light to factory gauges swap you will need to get a GM Helms factory manual and repin instrument panel connectors one and two. You will need to add a wire to the harness to run the tach, (the warning light cluster Firebirds don't have this wire since they used a different harness), and run either a 10ohm resistor from a switched igniton source on the fuse block to "start up" the alternator, or do like the factory and run a 10ohm "resistance" wire from the ignition switch. Also change your water and oil switches out and put in the oil pressure and water temp sending units. The idea of doing this type of swap to a warning light dash Firebird has been discussed before. It would be fun to see somebody actually do it. Here's a link: https://www.thirdgen.org/forums/v6/2...=leaving+idiot

Xophertony

looks like i have more research to do. i'll bust out my helms manual tonight and investigate what must be ripinned and edit my original post to include those instructions as well. i'll see about taking some pictures of the helms pages and uploading them as well.

EDIT*
from what i can tell the VSS system works completly different on the indicator cars. I think it would be better to just switch the dash wire harness out with one from a guage cluster car.

musclecarfan87

I appreciate all this....I'll wait until I get all the info before I start....We do have a LKQ junkyard around here (u pull it parts), so i might try to get the harness from there....will a 120mph cluster harness work for the 140 mph cluster?

Xophertony

any guage cluster harness will, just not an indicator cluster.

xbcrguy182x

my 86 firebird has a mechanical speedo....i dont get it...

Xophertony

neither do I. how do you know it is mechanical? is your engine carbed or MPFI? manual or auto? guages or indicators?

oldschool

All Firebird clusters be they gauges or warning indicators had cable driven mechanical speedometers from 1982 through the 1985 model year. Starting in 1986, Firebirds with optional gauge clusters had an electronic speedo. Full gauges did not become standard in the base Firebird until the 1988 model year, so 1986, and 1987 Firebirds kept the cable driven mechancial speedo if they came with the warning light cluster. In all years where both gauges and warning lights were available, two different dash harnesses were used. It's possible to rearrange the pins in the instrument panel connectors to create a gauges harness, however I don't know if anybody has gone that far with it . There's certainly no procedure for repinning a Firebird dash harness that I'm aware of on these boards. Additionally, the harnesses differ from year to year for cars with the V6.

Xophertony

thanks oldschool.

musclecarfan87

Hmmm.....I'm putting my swap off for a little while....I'll have to wait til I can take a trip to the junkyard.....I saw a 3rd gen 'bird there, with the 120mph cluster.....the wiring harness should work (hopefully).....what all do I need to get out of it for my 140mph cluster to work? (just makin sure I don't leave there without something important) And would it be better to just buy new sensors or can I use old ones out of a junked car?

jamie660r

iTrader: (1)

I did this in my 91 firebird and had no problem i went from a 120 to a 140.I swapped the circuit board and the face...

Xophertony

with how cheap those sensors are i would spring for new ones. the coolant one is less then 20$. not sure about the oil one.

you will need.
1. the VSS (vehicle speed sensor) off of the trannsmission
2. the wires for the VSS all the way back to the VSS buffer
3. the VSS buffer (yellow thing near the ECM, may be clipped to ECM)
4. the wires from the ECM to the guage cluster
5. the guage cluster harness

it may be best to take the ENTIRE dash harness out of your donor car. the best part about this is that you can pull the entire dash out of the donor car in the junkyard to make getting the wires out easier. and this will be a learning experiance so you can do it again on your car without breaking anything.

you will probably want to re-use as much of your existing wire harness as possable. once you have the entire harness out of the donor car you can cut all the electrical tape off and seperate the wires pretaining to the VSS and the guage cluster and set them aside. then you can do the same to your harness and place the guage cluster wires in place of the indicator cluster wires and put your modified harness back in. this way any changes that occured between years (lets say your donor car is a 91 harness, with VATs and an airbag and stuff) will not effect you. if you just switch the entire harness alot of plugs would be different.

TIPS:
take care to unplug the wires going to the pedal sensors before you start removing the dash. it is easy to break those sensors off of the pedals without knowing it. you don't want to drive around w/o brake lights. (i did this once. did not know for two weeks)

you do not need to touch the heater box wiring. it is independant of dah harness. you will have to unplug it from the heater controls in the radio pod.

you do not need to tinker with the speaker wires, they are independant on 82-86 models. the power wires for the radio ARE part of the dash harness. however if your donor cars harness id from an 87+ the same wires are present in it's harness (just extra speaker wires) so you can splice in your 86 plugs no problem. same deal if the original plugs have been hacked out.

you need to drop the steering column down to get the dash out. it would be best to remove it from the car. take care with the plugs that go into the steering column.

maitlandtron

Do you have to run a wire for the tach? And where on the cluster do you hook up that wire?

Xophertony

uhh... service manual is in my car. i'll post up tomorrow sometime, probably late... sleep now.

<--- tired all of the sudden, you ever get that?

Maverick H1L

iTrader: (8)

Well, since all you guys have pulled out your slow clusters, does anyone have an electrical 85/120 MPH bird cluster they are willing to sell cheap? I just need the speedo head and can't find one for cheap around here. My local yard has a cluster, but it's got the cable speedo in it, and I don't much feel like spending that kind of money on a cable and crap if I can just replace the speedo head.

jpfnk1682

iTrader: (1)

when i put the 140 dash cluster from an iroc to my 82 sc and turned it on only the tach, temp, oil and speedo worked is there a change in wiring from 82 till 87