Fuel and Temp Gauge Question??

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Mr.FT

Mr.FT

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Well i just spent 2 hours pulling my dash and replacing the voltage regulator for the gauges, Well I now have oil and low brake lights but no Gas and Temp gauges. I used a new electronic regulator. I working on a 72 demon 340 with the standard dash. Where should I go from here??

Thanks
 
Low brake light comes on when your brake pedal goes down to far ( I pushed the switch to make sure it worked) I think I hooked up all the grounds I'll have to double check. Would that cause the two gauges not to work? Also the headlights dim at idle, the wipers and blinkers slow down a lot at idle but as rpm increase they go back to normal. Could this all be tied together?

Thanks
Tom
 
I would check the alternator.
The grounds sound like they should be double checked first though.
Do you have a FSM to use for troubleshooting? It's a good idea to get one at any rate....
 
i recently had my temp gauge not working and my fuel gauge only reading 3/4th actual. I just reached my hand behind my dash on that side and pushed some connectors, now they both work fine. might check those connections.
 
Sounds like a problem in the gauge/ voltage limiter circuit to me. Time to do some real troubleshooting.

Pull the cluster back out and get them working before you put the thing together. Add a permanent pigtail ground from the cluster to the body.

Next, take your meter and see what voltage you get with the key on to the two gauge units. You can easily see where the PC board traces go from one place to the other. The "power" side of the two gauge units are both hooked to the same point---the output of the limiter. You should bet about 5V there with key on.

If so, ground the sender side and see if the gauge heads for the "up" scale end.

I'm betting you have a bad connection right there in that circuit, or you have a defective (or you damaged) the limiter unit.
 
There isn't a ground wire to check unless one has been added. the panel wont function properly while dangling from the harness connectors either. It needs its chassis ground , again unless a ground wire is added. Hope this helps.
None of this is related to the poor charging system though. The 2 wires attached to the amp gauge are relative to poor charging. Those connections need to be clean and tight.
 
Thanks I have to check out the chassis ground.
Redfish: The Gauge cluster was installed in the dash, new electronic regulator?
 
I dont know what voltage limiter you've installed on the panel or how it is connected. The brake lamp being dimly lit is a clue that something isn't right. Pics might help.
Did you reuse the noise supressor and where is it connected ?
 
Well it isn't the brake lamp, it's all the lights are dim, wipers are very slow, blinkers are slow ect. until I rev the motor a little then they all brighten and speed up. I did install the noise suppressor right where it came from. I'm leaning towards a bad chassis ground. Can anyone tell me where I can locate them? I checked the one from the neg. terminal to the block are there any others?
Thanks
Tom
 
Engine block to firewall , near blower motor.
 
RedFish:

Well at first quick look I don't see one from the block to the firewall, could it be anywhere else? I'm going to give the car a good once over as soon as I get some free time and see if they put it somewhere else.
 
I haven't seen one from the factory that didn't have a ground strap from the right head to the firewall. Even later models with added grounds from battery post to radiator support and elsewhere still have the first one installed. I have seen many that had that part left off with engine R&R.

Lets back up a bit too. If you have a low oil warning lamp instead of a gauge there, it doesn't get its power from the gauge "low voltage" supply.
The low voltage supply is only used for oil, water, fuel, gauges.
Other issues like weak charging system are not related.
 
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