Dash electrical DEMONS!!

Posted By: rabid scott

Dash electrical DEMONS!! - 03/04/14 01:36 AM

Okay, I have a '67 Valiant, none of the dash stuff was working when I bought it except the AMP gauge and SPEEDO.

Then one day I hit a bump and WAH-LA! The gas gauge started working, along with the BRAKE lamp.

It was glorious for several outings then stopped working. A few bumps later, they work. Then it stopped. Then it worked again.

So I've got intermittent grounding issues.

The MILLION DOLLAR Question...

How do I fix this? Can I add an auxillary ground to the dash panel?

Muchos gracias, a thousand thank yous, blessed be the one(s) who can answer my most (un)grievous question!!

Posted By: moparpollack

Re: Dash electrical DEMONS!! - 03/04/14 01:38 AM

On my 66 coronet it was the gas tank ground causing an open circuit.

Posted By: rabid scott

Re: Dash electrical DEMONS!! - 03/04/14 01:42 AM

Quote:

On my 66 coronet it was the gas tank ground causing an open circuit.

Does the BRAKE light circuit use the Fuel tank circuit as a ground as well? The two would either work together, or would not together as group. I'm assuming if the water temp gauge/sender worked it would or wouldn't work too.

How much would could a "Would Chuck?" would, if a "Would Chuck?" could Chuck Would? Hahaha... now I'm just getting off topic.... Hehehe....

Posted By: cjskotni

Re: Dash electrical DEMONS!! - 03/04/14 01:56 AM

If it's like the 71-74 gauges, they all ground as a unit (except for mech speedo and ammeter which has no ground).

When you say 'brake lamp', do you mean the light that lights up when you have the e-brake engaged? If so, that should have a wire that connects it to the parking brake switch which will connect to ground when the parking brake is engaged.

I would pull the gauge cluster and verify the voltage regulator (little box on back) is well-grounded...should ground to dash frame. The parking brake light socket should have 12V when the key is in the run position.

A wiring diagram would help here...

Posted By: moparpollack

Re: Dash electrical DEMONS!! - 03/04/14 02:00 AM

At this point clean them all! And when you are done stop by my house I can't get the gas gage to work in my D150.

Posted By: rabid scott

Re: Dash electrical DEMONS!! - 03/04/14 02:29 AM

Quote:

When you say 'brake lamp', do you mean the light that lights up when you have the e-brake engaged?

Yep, that's one. It also glows a nice cherry red when the rear brake fluid is gone.

Quote:

I would pull the gauge cluster and verify the voltage regulator (little box on back) is well-grounded...

That's what I was afraid of. Poop. No way of getting around it, I can't run a test jumper to ground out something? A temporary fix I can use permanently?

This car suffers from "Previous Owner Syndrome" because the homeboy "refinished" the dash assembly as well as a number of other choice "repairs".

Posted By: stumpy

Re: Dash electrical DEMONS!! - 03/04/14 02:34 AM

Try tightening the screws that hold the instrument cluster to the dash.

Posted By: NITROUSN

Re: Dash electrical DEMONS!! - 03/04/14 05:48 AM

Quote:

Try tightening the screws that hold the instrument cluster to the dash.

Thats to easy....

Posted By: rabid scott

Re: Dash electrical DEMONS!! - 03/04/14 06:58 AM

Quote:

Quote:

Try tightening the screws that hold the instrument cluster to the dash.

Thats to easy....

That was the first thing I tried!

I was contemplating a gas gauge to hang under the dash 'cuz they're only $20 but I fingered I may as well and try a fixn'er right first.

After that works, I can try and find the source of the brake fluid leak....

Posted By: Andrewh

Re: Dash electrical DEMONS!! - 03/04/14 04:42 PM

then yeah, run a temp ground to the instrument cluster frame.
not the dash frame.

there is metal behind the plastic on the outside.
see if you can find a screw you and set a ground on and see if that makes it all work again.
or pull it and find the ground screws for the circuit board and put one there.

Posted By: That AMC Guy

Re: Dash electrical DEMONS!! - 03/04/14 11:58 PM

I'd take the cluster out to inspect what's going on. A lot of times, the pins on the board that go into the harness connector are loose or broken.

You can either solder the pins to the board (traditional route) or a friend of mine came up with an even better idea was to use tiny machine screws in the backside of the pin. That stretches the pin out and makes it much tighter in the board but also gives you that solid mechanical lock.

I'm now thinking a combination of screws & solder would make it so you'll never have to pull a cluster again!

Oh, and I also second the vote for adding a secondary ground wire/strap.