1964 mustang wiring problems

[scottymac]

hey guys i need some help here. I have a 64 stang that I replaced originalwiring with a painless harness.....I know I should have put the priginal back in but since this car is a restomod with many extras it made better since to go this way.

anyway after all is installed the car runs fine but the fuel gauge goes all the way to full and the temp gauge goes all the way to hot as soon as the key is turned on. I have checked the wiring and ran a jumoer wire to the fuel gauge to make sure the new wire did not have a break in it, still did the same thing. also I changed the power source wires on both to a different location and still had the problem. Im lost at this point, all gauges worked prior to changeing harness. I hace checked the constant voltage regulartor on the dash and it has 12 volts in and out??? is that correct or should it be reduced as it comes out. please help if you can, thanks

 

[2+2GT]

Sounds like your CVR supply to the gauges has gone to a full 12V.

 

[scottymac]

any idea how many volts it should have?

 

[HookandLadder]

6 volts. The CVR drops it down. You may need to replace it, but make sure it is securely mounted...ie...grounded to the dash assembly.

 

[dewdrop]

CVR operation

Keep in mind that the output of the CVR is not 6 volts. It is an AVERAGE 5.8 volts. It does this by allowing 12 volts through in a "on-off" fashion. If you use a test light on the output, you should see a "blinking" light on and off. On a meter you will see the voltage jumping around but around 6 volts. If the light doesn't blink fairly quickly, then the CVR is not working right. If it's on all the time, then the unit is bad. If it blinks slowly, it's bad.

Just did a bunch of trouble shooting on some bad ones and a good one.

 

[Mil1ion]

The ICVR is grounded to the wrong area.

It should look like this when it is hooked up correctly.

View attachment 257965

 

[scottymac]

thanks guys, I replaced the CVR and all wgauges work great now. Last circuit to hook up is the horn, and hopefully I can get back on the road.

 

[patrickdmc]

hey guys i need some help here. I have a 64 stang that I replaced originalwiring with a painless harness.....I know I should have put the priginal back in but since this car is a restomod with many extras it made better since to go this way.

anyway after all is installed the car runs fine but the fuel gauge goes all the way to full and the temp gauge goes all the way to hot as soon as the key is turned on. I have checked the wiring and ran a jumoer wire to the fuel gauge to make sure the new wire did not have a break in it, still did the same thing. also I changed the power source wires on both to a different location and still had the problem. Im lost at this point, all gauges worked prior to changeing harness. I hace checked the constant voltage regulartor on the dash and it has 12 volts in and out??? is that correct or should it be reduced as it comes out. please help if you can, thanks

Just curious, did you keep original generator and dash? I'm wanting to do full gauges like a 66 with alternator but wasnt sure which painless harness to buy. Painless would only tell me they dont have 64 and the 65 and newer is different. Thanks!

 

[Olivethefet]

This thread is over 10 years old at this point. You would probably do better starting a new thread in the classic mustang sub forum detailing your specific issue.

I dont know the answer to your question, but does your car have a generator? When was it built? I have a 65 that was built in August of 64 that came factory with an alternator. Mine isn't considered a 64.5. I know the true 64.5 cars came with generators.

 

[patrickdmc]

This thread is over 10 years old at this point. You would probably do better starting a new thread in the classic mustang sub forum detailing your specific issue.

I dont know the answer to your question, but does your car have a generator? When was it built? I have a 65 that was built in August of 64 that came factory with an alternator. Mine isn't considered a 64.5. I know the true 64.5 cars came


Mine has the generator. But I want to change to alternator and want the 66 style gauges. I was just curious which painless wiring you bought. It's ok, I think will just order a 66 full wiring since I'm starting from zero.

 

[rgsauger]

Not sure why but 100% sure that the transducer side of the gauges are going straight to ground. If your icvr was not working, the gauges would not move at all. Straight to ground will peg a gauge just as you described.