This is on the 94 V6, I'm doing some basic troubleshooting using information the instrument cluster is giving me.

First success: The temperature gauge was inop. I grounded the single green wire off the gauge temp sensor/sender located the power steering pump, and the temp gauge pegged at max. Working gauge. Replaced the sender and now the gauge operates. Win!

Problems:

1. BRAKE warning lamp. It was constantly on regardless of the position of the park brake handle, but, setting the brake would cause the lamp to be brighter. I assume that's due to a better ground, or more power to the lamp if the source for illumination is both the park brake switch and the ABS module. I flushed the brake system and ABS pump and the light is now off. But now the lamp will not illuminate at all. Either a park brake switch issue or burned out bulb?

2. After flushing the brakes, I lost the gauge backlight for the voltmeter. I'm going to assume this was happenstance and unrelated, although, next problem:

3. CHECK GAGES remains faintly illuminated intermittently when the engine is running. All gauges are normal. Fuel is at 1/4, so I will add fuel to rule out fuel level, but the light was illuminated north of 1/4 tank too.

4. SERVICE ENGINE SOON lamp is completely inop (is this a blessing in disguise?!). I suspect a burned out bulb, although that's starting to appear fishy since all the problems with lights are in that one area of the cluster. OBD scanner is not indicating any faults.

I hate to pull the cluster because it requires removal of the upper dash panel in the 93-96 cars, but I think that may be my next course unless anyone has any input or ideas on how to diagnose without doing that.

 

Do you have a copy of the 1994 factory service manual? If not free download courtesy of member GaryDoug:

https://www.mediafire.com/?40mfgeoe4ctti

2000 is there as well.

Gary has also written scanning software with versions for the LT1 and the 3.4L V6. In addition to the PCM is can pull codes from the EBCM and airbag system. I help people with the data log from the LT1 version. It’s very good.

https://www.firebirdnation.com/threa...6#post-1593316

 

Thank you. A good reminder that I do not have the 94 service manual (I have the 93 and 2000), so I grabbed that one. Scan9495 is what saved my ABS nightmare with my 93 about 6 years ago... You and Gary are awesome resources, many thanks for all the pointers over the years.

I have the same problem now as I did back then... I need to get a windows box so I can run the scan software. I borrowed a work laptop back then...can't do that now. I'll buy something on the cheap to use in the garage as I *will* be using the software again.

 

All issues trace to the cluster itself. I'm hesitant to pull it because the upper dash is original, and in one piece. I can tell it's very brittle. Will probably shop for a replacement and make sure I have a suitable one before removing it. I was SO hoping I didn't have to do that.

Anyhow, the car wouldn't crank at all yesterday, no noise, nothing. I pulled the dash fuse cover and wiggled the PCM IGN fuse, and on the next key turn it cranked right over. Wiggling the fuse block and the gages fuse causes the brake light to go out on the cluster. I know the cluster connection is right behind that fuse block. The check gages light also goes out when I do that.

I've noticed the speedometer reads fast too, anywhere from 5-8+ mph at speed. Gearing is stock, tires are stock Z28 size (245/50/16) and shouldn't account for the kind of variation I'm seeing versus the stock V6 235/55's. Yesterday I had the scanner feeding live data while I was driving and had a passenger with a GPS speedometer on his phone. The phone GPS speedo and the PCM Vehicle Speed on the scanner are basically even, so I think the cluster has some electrical issues beyond corroded connections. I have a cluster out of a 96 so I'll see what I might be able to salvage and swap over. Otherwise there's a low mile cluster on eBay and I'll swap that. I believe the odometer/trip can be removed and installed on the new cluster to preserve the original mileage. I'll practice on my junk cluster from the 96.

I know I'm posting to a mostly empty theater. I'm reliving my love of these cars with this little old '94 and posting my thought process and diagnosis adventures for anyone who might stumble on them.

 

Last post on this one, update.

The brake warning lamp was actually the brake switch at the ABS module under the hood. Removing/installing and cleaning it seemed to restore proper operation, and the brake warning light stays off.

The backlighting and other lamp issues were all corroded contacts on the PC161 bulb sockets and printed circuit board. Cleaning the contacts fixed them all - didn't even have to replace bulbs.

None of that truly mattered. I somehow found an 1,800-mile gauge cluster out of another 1994 and I'd believe that mileage is actual. The circuit board looked brand new, no crispiness or browning from the backlighting, and the odometer gears still had lubricant on them. I swapped the odometer out of mine into the new cluster, and everything works as intended. It's visually stunning to see non-faded gauge needles. Looks like 1994 all over again!

I have the old cluster as backup for parts including the odometer motor. I had one of those go bad in another car, so I feel better knowing I've got a spare around!

I'm still a little surprised / alarmed at how much time has passed these cars by. Parts are getting much, much harder to find, and this board is fading into silence. When the day comes, we'll all have to pour a glass of Crystal Pepsi out for it.

 

I’ve been following this…. didn’t butt in since you appeared to have everything under control. Well done. Thanks for following up. Maybe somewhere in the deep, dark, distant future someone with a similar problem will find this.

Couple thoughts…. I don’t believe it was necessary to disturb the upper dash panel to pull the cluster. Correct? I think I must have pulled the cluster for some reason…. I know one of the clips broke off the surround when I was pulling it off. It had to be 25+ years ago. Time flies. Did you use Scan9495 to identify the problem with the brake switch?

Enjoy the holidays.

 

No worries, just posting about my adventures, didn't expect anyone to respond.

I didn't use Scan9495... problem is as it has always been, I don't have a windows box around. I haven't needed that level of diagnostic ability yet. I'm currently using an OBD-I scanner with live data, and this '94 works with it just fine. Believe you me, first time I get an ABS code or need a deeper dive, I'm buying or borrowing a windows box so I can use the software.

The cluster needed to be pulled anyway, I wasn't going to live with half the backlighting gone. The proper procedure for pulling the cluster is to remove the upper dash. It conceals the mounting bolts for the giant swoopy black gage surround/bezel with the vents. Now, it might be possible to undo the lower fasteners on that and gently bend it upwards to reach some cluster screws, but there's high risk of breaking mounting tabs on that bezel. Sophie's choice.

I installed the new dash pad yesterday and it's decent quality and the color is good. No more worrying about that pad cracking if I sneeze on it. And, if the cluster has to come out again, the pad should be easily removed/reinstalled!

Happy Holidays. I'm gone for a few weeks and won't be working on the car so I may not return here until the Spring!