I have a 1991 Camaro RS 3.1L and I have a huge problem. It all started when one day the speedometer stopped working and after about 10-15 minutes it just started working but bounced up and down then calmed down and started working fine. It does this every day. Then one day when I turned on the headlights with the car running the buzzer that reminds you to turn off your lights went off and won't quit until you turn off the lights. Now as soon as you turn on the ignition without starting the car the Gauge fuse blows. None of the gauges work with this fuse blown. The Tach, Oil Pressure, Battery, Fuel, and Oil Gauge do not work when this fuse blows. As long as this fuse is blown the buzzer for the headlights buzzes. When you can get the fuse to stay the buzzer is off as well, however, the fuse blows every time now.

I have taken the cluster out of the car and looked for burnt or loose connections and found none. The fuse still blows without the cluster in the car. I took the headlight switch out as well and the fuse still blows. I have traced the wire from the Gauge fuse in the fuseblock and didn't find anything loose or burnt.

I really need to get this fixed since it is the only car that I have. Any help would be appreciated

 

Has anyone come up with some solution to this problem. It seems that it is a common problem. Any help would be appreciated.

 

Not really but Ive been pondering it for a day and a half. The best I can think of is a blown ECM. If you cant find anything bad in the cluster or speed sensor on the tranny like a pinched wire it's gota be an ecm problem all wires go to and come from the ecm but to many things just dont add up.
Oh well just posting to let you know were trying.
I would check the ecm for burnt wires, pull the cover and see if it smells burnt. I would hate to tell you its the computer and you grab one and it doesent help.

 

Okay, I guess it must be common, because mine does the same thing. Almost exactly.

What I can't figure out is what is different. Before I swapped motors, everything worked. Now that I've put the new motor in, I get the same symptoms as you. Except that only my Tach, fuel gauge, and voltmeter don't work.

I can't help but wonder if it's something I did. I studied the wiring diagrams and the signal for these gauges do not come from the ECM. They come from (for before 1988) a single brown wire that connects to the output of the voltage regulator. Although, I don't see where this wire supposedly is or goes to when I look at my alternator. Still figuring that one out.
Anyway, it's supposed to go first to the voltmeter, and then changes to a pink/black wire that then provides power to everything else.
So in your case, with ALL your gauges out, you may have a problem with a short on that wire, probably between the fuse box and the voltage regulator (inside the alternator probably).

In my case, since only some of my gauges don't work, it could be a common ground. And THAT's something I may have done, or not done. There were a crapload of ground wires that went to the back of the block onto a stud. If I didn't replace one of those that is common to the gauges that don't work, then that's it.

But the symptom that makes the buzzer go off when the lights are on is the same. It must be a warning system for something like that.

Look very carefully for a brown wire that has some exposed copper. If you can't find the short, but you find the wire and where it goes, and can verify that it's shorted to ground, it would be very simple to cut it out and run a new wire to the voltage regulator.

I'm still hunting mine down. But I don't think it's the ECM. If I find it, I'll post it here and let you know what it was.
Look for grounding problems and shorted pink or brown wires.

 

...OR is the voltage regulator INSIDE the ECM???
Hmmm.

I know Chrysler puts the V regulators in their ECM's, maybe GM does too. I'm not convinced it's a bad ECM, but if the regulator is in the ECM, then maybe it's possible.
Does anyone know?

(Sorry, I'm still getting to know these cars).

 

I seemed to have solved my problem. There is a group of four wires that connect to the tach. They are located between the firewall and the engine on the passenger side. They go to a connector on the tac. I found that these wires appeared to have become somewhat welded together. I seperated the wires and taped each one of the so that there were no bare spots (not that I saw any anyway) and they couldn't directly touch each other and everything started working and the fuse has not blown in the last week. This seems to work for me and I hope it works for someone else.

 

Wow, okay that's possibly the reason for my problem too.
Except in my case, I'll bet I reversed the brown and the white wire to the coil of the HEI when I installed the new engine. That would definitely prevent the tach from working, and might also prevent some of the gauges that use that from working also. Could be a simple 10 second swap of wires and everything might work. Worth a try.
Thanks.

 

Nope.
Nothing I've found has been miswired so far. I checked for a short in the wires that go to the HEI. Nope. Checked my engine grounding points. All there, all intact. I'm beginning to wonder if the printed circuit board behind the gauge panel is bad.
I guess dashboard surgery is the next step.

 

Sorry to hear that didn't fix your problem. Mine is still working after a week so either I fixed the problem or I just masked it somehow.

I still have a problem with my speedometer though. When I first start driving it is not working but after about 10 or 15 minutes it will suddenly start working but it fluctuates up and down and when it gets above 45 MPH it shifts into overdrive and downshifts when it gets below 45 MPH. Then after a while it will settle down and everything will be fine. Does anyone know how I can test the Vehicle Speed Sensor?

 

FYI: If you leave the brown wire that runs from guage cluster to alternator disconnected, car will appear to run fine at first. But you'll find out the hard way that the alternator is no longer charging battery when engine is running. Hook up a voltmeter to check for sure.

 

I finally gave up trying to find the problem and took it to a good auto electric shop. What he found is a nightmare. The previous owner had indescriminately cut into wires behind the dash trying to modify stuff for these dumbass switches on the console, and did a real hack job on the stereo. In order to save a stupid $40 charge at the local Soundtrack, he caused SEVERAL hundred dollars worth of severe damage to the wiring harness.


I bought the car from a guy on this forum that was a CSU student in Fort Collins, Colorado. If he still frequents this forum, I'd like him to know that he's a real moron.

Had I known the electrical nightmare waiting for me, I would not have bought this particular car at all. Some people should not be allowed to own nice cars.

Okay, grumbling over for today. Hopefully, the electric shop will get done with it today, I can get gouged for my bill, and it'll all be fixed, once and for all.

 

$1004 fixed the massive electrical problem that the previous moron/owner caused when looking for wires to wire up his thumper stereo. $1004 includes a wiring harness and install labor. The old harness was too destroyed to salvage.

All to save $40 install charges at Soundtrack.

My $1400 IROC deal is no longer a good deal.
After swapping the dead 305 for a 355 that I built, after paying big bucks to get a true header system and new exhaust, and after paying even bigger bucks to fix Bubba's wiring expertise,
I could have gone down to any dealership and bought an unmolested IROC for about the same investment.

Oh well, at least I think it's fixed...I think.

 

Underdash electrical work is physically demanding of your body. Many older mechanics try to avoid it whenever possible.

on cost, you could have gotten a clean camaro dash harness for around $100 from junkyard. install is not too bad a job if you don't try to rush through it.