E Body Rallye Dash Guages Not Working? Bad Ground?

3 of the 4 guages (oil,temp,fuel) are not working on my '70 Cuda w/rallye dash.The alt/chg guage appears to be working fine but the other 3 are pegged to the bottom.Is this a dash frame ground issue or any ideas?Thanks

It might be that the current limiter is not pluged in? There is a 3 plug (to each of those gauges), small black wire harness that connect the current limiter to instruments. Perhaps the connection is bad or corroded or not connected? If it looks right, it might be a bad current limiter. The cluster housing gets it's ground when you attach the screws to the dash frame. Do the instrument lights work?

If your car was just recently restored, you very well could have dash ground problems. The dash frame gets its ground from where it bolts to the door jambs at the bottom corners. If both the dash frame and the door jambs got new paint, it is possible that the frame is insulated from the body of the car. I always tape up the contact points of the dash frame and the body of the car where the two bolt up before painting. Then I put a very thin coat of electrical silicone grease on the unpainted surfaces to help the electrical ground connection and to keep the bare metal underneath from rusting. If you know that's not what's wrong, I would look at the voltage limiter to see if there's a problem there. Good luck.

Thanks for the info guys.I just checked and the dash/guage lights do not work also.Headlights,radio,turn signal,etc all work.Does this narrow it down at all?I did install a new electronic guage voltage limiter from Real Time engineers.And yes,it is a recent,well 8 years in the making,restoration but fired it up for the first time yesterday.

Jim,
Try this: Attach an electrical wire to a known good ground source. Attach the other end of the wire to an exposed metal part of the dash frame. Even if you just jam it into a screw hole and fasten the screw. Select a screw that is on the dash frame, like underneath. This will give you a temporary circuit to test if it is a dash frame to body ground problem.
If this works, unbolt the dash frame from the body and scrape away the paint from the dash frame. The bolt will have a good ground in the body already from the threads. The bolt head may not be grounding the dash frame because of thick paint.
Ola

Also make sure that the corner switch pod is properly grounded.
Locate the Philips head screw closest to the driver door right under the switch pod and just above the heater control.
That screw is the one that grounds the switch pod and this should help with the lights.
Check the voltage limiter with a test light. Even though it is new there maybe a bad power wire going to it.
Are you sure the gauges are okay? Try hooking each one up to 3 volts and see if they react.
Jules

OK,finally got a chance to check on some things and like an idiot I never checked the 20 Amp instument fuse which was blown.Install new fuse,clock starts up,map light works,light over the switch panel comes on,etc (A01 light pak car)..but when I go and turn on the headlights,the fuse blows.Any ideas.Thanks

Would having the underdash A01 harness plugged in incorrectly cause this?

Well I got the blown fuse problem solved.Turns out it was blowing the 20A fuse for the taillight and found a bad wire in my harness.Replaced the harness and that problem is solved.I still have the guages not working (Oil/Temp/Fuel) problem going on.Another quirk I discovered today and think it may be related is that my radio will stay on,even with the key if the off position until I remove the key from the cylinder.I can manually turn off the radio by the knob at anytime but shouldn't the radio got off once the key is in the off position?I have double checked the fuses and the dash ground to the body.Any suggestions???

Well I removed the A01 harness for now just to eliminate that from the mix.Still no guages.I did install one of RealTime Engineers electronic voltage regulators before I reinstalled the dash earlier this year.Could it be I may have got a bad one or anybody else have any problems with these?The dash light bar works as does the panel dimmer.Also,what are the correct colored wires the radio plugs into?I think I may have had that plug in wrong also,but it did work and play just that it stayed on until I removed the key from the ignition.And yes,I can't follow a wire diagram worth a damn.Thanks for any help!!

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Well I removed the A01 harness for now just to eliminate that from the mix.Still no guages.I did install one of RealTime Engineers electronic voltage regulators before I reinstalled the dash earlier this year.Could it be I may have got a bad one or anybody else have any problems with these?The dash light bar works as does the panel dimmer.Also,what are the correct colored wires the radio plugs into?I think I may have had that plug in wrong also,but it did work and play just that it stayed on until I removed the key from the ignition.And yes,I can't follow a wire diagram worth a damn.Thanks for any help!!

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There is a two wire connector for radio power. The red wire powers the radio and should be switched 12 volts. The orange wire is the dial lamp feed and it goes through the dimmer switch to 12 volts and varies as the switch is adjusted.
Craig