[hoffmandirt]

The gauges in my 1979 Z/28 are inaccurate. The volt meter is down at 8 volts most of the time, the temp gauge stays in the low 100s, the fuel gauge fluctuates back and forth, the speedometer works for a few miles then goes back to zero, and the dash lights only work half of the time. Would the circuit board on the back side of the gauge cluster be the culprit? How can I trace down the problem? I also want to mention that sometimes, not often, everything works as expected.

 

[dawg]

loose ground wire!
check the connector and trace out the ground

 

[cobalt327]

The gauges in my 1979 Z/28 are inaccurate.

The speedo is cable driven- it'll be a separate problem to the electrical issues w/the rest of the instrument panel. It has a rotating magnet affair, might just need cleaned and removal of anything that is blocking the rotation of the movement and/or needle.

In the back of the gage cluster, there's a male plug that's part of the dash and a female receptacle that's part of the flexible printed circuit board and removable portion of the gage cluster. The connection to the various gages and lights are made there, and this is a problem area for this car- and many that are like it.

After you do the ground wire chasing and repairing if needed, you can see what's left of the flexi-PC connection.

There are new flexi-PC's made for that dash, IIRC, but they're not cheap.

I heard that the crap that's made for repairing the rear window defroster strips can be used to repair the flexi-PC contact points, but have not tried it myself. While in there, replace all those little push-in bulbs w/new ones. Try not to unscrew the bulb receptacles any more times than absolutely necessary- the contact area around them on the PC is fragile- like the main connector.

 

[fiscus]

Its not uncommon on these cars!