Hurst/Olds 73/74

I purchased my first G-Body in June, a 1985 442. When I got the car, none of the dash gauges worked. After much patience and tinkering, I got all of the dash gauges working, including the tach. They have worked fine for the past 2 months. This week, I finally got the factory AM/FM Cass. working (pulled fuse out and plugged back in, connection was corroded). The reception was poor because my power antenna was broken off, so I also replaced the factory power antenna this week (that was a chore!) Everything worked fine for the afternoon, then I started having problems on a trip into town. Now the radio only plays static and the display (clock/radio readout) doesn't work. Also, the same evening, all of the dash gages stopped working!!! I had pulled the radio out and back in, but didnt' mess with anything close to the gauges! The tach and speedometer are the only gauges that work. The gas, oil, and amp/volt read zero, and the temp gauge is pegged at hot. Am I dealing with a bad ground somewhere? If so, where do I look? BTW, the antenna is plugged in and also plugged in on the other end to the back of the radio. I have pulled the radio out several times since this happened, made sure everything was plugged in, with no success.

Sugar Bear

Yes this may be a bad ground. Gauges pegged to full indicate an open circuit. Check (clean and tighten) the small (pigtail) ground/negative connection from the battery to the fender, look for a braided connector from the back of the engine to the firewall in the vicinity of the brake booster and look for ground connections near the emergency brake pedal.

What was the problem when the gauges did not work the first time?

Good luck and keep us posted!

Hurst/Olds 73/74

The problem initially was a combination of bad circuit board behind the gauges (repaired), chewed wire behind gauges (repaired), broken wire to the rear of the gas tank (repaired), and cut tach wire going to distributor (repaired). Thanks for the much-needed advise! I'll check into it tonight or tomorrow after work! After all the work I've done on this car, this was just crushing and extremely frustrating!

ThePackRat

It could just be coincidence that the radio & gauges chose to act up at the same time.

I will tell you the gauges can be finicky.

First & foremost on those is the issue with the tach being erratic due to the jumper pin on the back (6 vs 8 cylinder).

The other issue can be the circuit board contacts not making proper contact where it meets the dash plug/pins.

Such as :

Sometimes the contacts need some cleaning with a pencil eraser.

Other times the contacts become too flat/ pressed down in the cluster cavity & need to be tweaked outwards slightly to make better contact with the pins on the dash plug.
(hopefully that description makes sense)

Use your judgement if the circuit board is in good enough shape to be cleaned &/or tweaked.

If it's not in the best of shape fartin' around with it might make things worse.

I've even had finicky issues where simply loosening the (4) screws - nudging the cluster a bit & re-tightening them fixed things.
(works best to have the car running with the lights on)

Hurst/Olds 73/74

I tore into the 442 last night. I checked all three of the aforementioned ground wires (pigtail off battery, engine-to-firewall, and dash frame near e-brake). I removed, wire brushed, and re-attached. I also removed the radio and heater controls and checked all of the wires behind them. Then I left the radio attached and blaring static while I wiggled every friggin' wire I could find under the dash and around the power antenna, with no luck. I then pulled the gauge cluster and inspected it. At first I thought the gauges weren't getting a good ground, but then I realized that the tach was still working and it runs off of the same circuit board ground line as the other gauges, so it shouldn't be a ground problem there. I'm not very electrically minded. Sugar Bear mentioned an open circuit. What does that mean? Bare wire bumping metal somewhere? I like the car and don't want to have to run it off a cliff, but it's testing my patience.