Instruments not working

[postie]

When I purchased my car the instruments were not working. When I removed the panel I found that someone had tried to do some rewiring and it was a total mess. In doing some research I found out that a lot of cars of that era did not run the instruments on 12 volts but rather had power running through a resistor to reduce the voltage to 5-6 volts. A previous owner had removed the resistor for some reason. I installed a new one but found the resistor was getting so hot you could not touch it. The gauges moved but not up to 'normal' readings. If I removed power to one of the gauges the resistor seemed to be normal temperature but the instruments were still not reading where they should be. I have now found out that if you have run straight 12 volts to your instruments you can burn them out. I am wondering if this is now my problem. Has anyone come across this issue?

[Groover]

Yes, the original gauges were 6 volt (holdover from when the entire car was six volts). There is supposed to be a voltage regulator that reduces the 12 volt electrical system to six volts before it hits the gauge cluster. It's a little rectangular item bolted directly on the back of the instrument cluster. They are very fragile and burn out easily. If yours is out, then you may be sending 12 volts to the gauges. If so, they would all peg. In short order the gauges would burn out as well. Might be time to pick up a multi meter so yo can see what is going on.

They do sell replacements for the voltage regulator. But i'd check everything before you put in a new one, or you may just burn out the new one immediately.

Here's my thread on how it all works.

http://www.cometcentral.com/forum/viewt ... ive#p51735

[postie]

Thanks for re-posting this. It's very informative. I am getting 12 to 5.32 volts on the CVR. When all 3 gauges hooked up the CVR is very hot. Disconnect any one of them and it is fine. All three gauges are definitely not reading where they should. I just filled the fuel tank and it is reading 1/4 full. When I briefly run 12 volts to them both the fuel and temp will pin full. No movement on the oil pressure with 12v but it will move hooked through the CVR and the engine running to slightly above low. I hate wiring issues. Lots more head scratching yet to come.

[postie]

I was able to acquire an instrument panel from a parts car. I guess whoever installed 12v straight to the instruments on my car burned them out. The replacements are working fine now except the voltage gauge. It appears there should be some kind of small electrical cylinder bolted to the back of the panel. It was missing from mine and the parts one I picked up also. Any ideas what this is?

[loman]

Are you sure it is a voltage gauge and not an ammeter? The 65's have a ammeter gauge and there is a thick black wire that passes through a loop on the back of the gauge. The amps passing through the wire induce current that is registered on the gauge.

[postie]

2019-04-28_09-02-25_946.jpg (159.27 KiB) Viewed 2570 times

Sorry I should have been clearer. It's the amp gauge

[SASSY]

The power wire from the generator( I think ) just runs through there to ign,,,? Anyway its just a wire some one will have the complete answer.

[SASSY]

I just googled it, shows the ammeter with the wire
https://www.google.ca/search?q=1964+Com ... oBM:&vet=1

[tomb22]

The electrical cylinder is meant to have the feed wire from the battery side of the starter solenoid go thru it to operate an amp gauge and then that feed wire feeds all the rest of the circuits in the car. So your amp gauge is looking at all the current being used except the starting circuit. That's how it is wired in 65.
tom

[postie]

Thanks for the replies. I think I will wait until it is off the road later this year before I attempt to fix the Amp gauge. It is just nice having the other more important ones working now.