Sparks, Smoke...

[Grabinov911]

OK. So I took out my 1970 RR Rally (Rallye) gauge cluster to repair the bad dimmer and replace the bulbs. This went well. I reinstalled the cluster and hooked everything back up, including the "Alternator" gauge, which was connected but not working when I removed the panel in the first place.

When I hooked the ground back to the battery, the "Alternator" gauge jumped, sparked and started to smoke. I raced back and pulled the ground off of the battery - luckily i didn't catch anything on fire. I don't really care about the (Dangerous) "Alternator" gauge, but now my other three rally gauges aren't working - no gas gauge, no oil pressure gauge, no temp gauge. They were all working before I started.

Is there a fusible link for these somewhere? The fuses are all good. The tach works, the wipers and sprayer work, the lights, dash lights and dimmer work... Did I kill it?

 

[Ron 73]

Here is a wiring diagram, there is one Fusible link that i seen just glancing over it (around battery area + side) there may be another, I would do some checking to see just what did this, sounds like a dead on short for sure. Hope it is just a link.

 

[Grabinov911]

Yeah I removed the wires from the Alternator Gauge, which is probably bad. This got rid of the smoke and sparks (that's some consolation at least). Unless the fusible link controls only those gauges, I fear that I probably killed that section of the panel, because everything else on the car works.

 

[Ron 73]

If you spliced into wires to hook the gauge up and now its unhooked because of this, if it was put back together, the wires you spliced into for the gauge i wonder if it would work.. BUT, if it wasn't the gauge and something else, hooking it up straight could make matters worse. gauges do go bad and you can buy ones that arent good, but, i really hesitate to tell you to do it, unless you know for a fact, it was the gauge doing it! If its some other problem in the wiring you need to find it, this diagram should be able to help you trace all the wiring and make sure everything's ok before trying it, maybe someone else will get in and have a better idea. I would go over all the wiring now that this has happened, before trying anything it could have caused problems someplace else to make it dangerous.. Just my suggestion, you don't need a fire, check all of them... Good luck.

 

[bigmanjbmopar]

I don't have a rally cluster but I would think after that melee you fried the voltage limiter on the board.

Does it look like this?

 

[smyythe68]

Yeah, I would for sure look towards the voltage regulator. Its the small metal box hangng off of the back of your dash. Your better off getting a electronic retrofit one anyway. If your handy with a meter you can check for continuity across any one of your gauges as the voltage regulator runs all of them. If one is good it is quite likey the rest are good also. The other thing you can do is to get a 9 volt battery and touch it across the back of the gauge for a second or two, with the igniton off, and you should get immediate difflection. good luck!

 

[Grabinov911]

Bigman: My cluster is the rally gauge cluster, but it DOES have the silver tube on the back which it sounds like Smyythe68 is referring to as the voltage regulator.

Smyythe86: Genius! I'll check each of the gauges with a continuity tester and then a 9 volt battery. I take it that the voltage regulator is designed to control the 12 volts to let only 9 volts to the gauges and that it's the tube like thing in the picture that bigman posted?

 

[smyythe68]

Regulator is actually for 5 volts, but 9 for a brief time is ok. The regulator is more of a rectangle, to the left, the cylnder is actually a capacitor or condensor. It smooths out the voltage coming from the regulator. It is no more than a glorified turn signal. Its a thermal strip that applies voltage heats up then turns off and repeats this continuously, kind of like a Morris Code voltage type situation. This being mechanical, is a weak component to the system. The new electronic ones supply constant 5 volts all the time. Also if you can remove the regulator before testing you will eliminate it from being a short or false reading and shorting out your little 9 volt.

 

[Grabinov911]

Copy. I'll look for the voltage regulator.