instrement panel ground issuses

[derek73o2]

my tach just went dead on me my temp gauge was pegged and now went dead does anyone have pictures of how they fixed the problem

[Mike Self]

If the main ground for the whole cluster has failed, nothing (including the lights) will work. So the two failures may be coincidental....or not. Make sure the multiprong plug on the back side of the cluster is fully seated, and the small three wire connector on the back of the tach is also connected. If they check out, try these:

1. Dead tach--did you check the (usually) black wire at the dizzy? If it falls off, no tach action.

2. Temp gauge. Check to see if the wire has come off the sender unit or is all corroded and gnarly looking. Clean it. Also try grounding the sender unit to the block with a jumper wire and see if that helps. If it does, then you'll need to remvoe the sender and clean the threads (lower coolant level first or you'll have a mess). If that's not it, check archives for details on the fix at the gauge end...basically it's a Y-shaped harness with the short legs fastened to the two brass nuts that hold the temp and fuel gauges in place, and the long leg going to a convenient body ground. The usual problem here is a flickering gauge, not a pegged one.

cheers

mike

[eurotrash]

Fuse #4 (I think) on my daughters 76 kept popping and causing a similar issue. All but the speedo quit on us. Turned out to be a faulty termination on the wire I added for the tack when we took out the clock.

Not sure if this input is worth a darn to you or not..

[derek73o2]

the tach ended up being a fuse but the temp gauge still just pegs into the red. it a brand new sending unit the wires clean im pretty sure it a ground

[eurotrash]

Gotcha. I also added a ground, as a preemptive strike.

[derek73o2]

can you explain how you wired it or by any chance know of any pictures that someone has

[eurotrash]

It's rather simple. Just find a place on the back of the cluster to fasten a black or brown wire, and run it down with the speedo cable to a ground location under the dash. Any body screw in the firewall or steering column nut will do. Leave yourself plenty of length so you can pull the cluster out again later without having to disconnect the wire from the car.

Doing a similar procedure behind your front turn signals can relieve issues there as well, should any arrise.

[derek73o2]

ok cool thanks

[eurotrash]

No problem. Report back on the progress.