I'm working on a 69 ford f100 and the fuel gage quick working. I replaced the sending unit and it worked for a while but then quit again. So I check the constant voltage regulator. there is a what looks like a reristor attached to the CVR which is busted, it is just a bunch of wire wraped around a pice of fiberglass(it looks like a factory piece) so I bypass this thing and I get 12 volts out both sides of the CVR. My question is do I need to replace this reristor looking thing and how many volts is suppost to be on the out going side of the CVR, I thought it was suppost to be 5 volts.

 

I think it is 5 Volts also. Controlled by instrument panel Voltage Regulator.

 

I dunno, but they are pricey little buggers!

My TEMP gage is a little on the low side and the FUEL gage never indicates above 3/4 w/ full tank, so after my genius troubleshooting, and wonderful powers of deductive reasoning, figured that had to be it.

It wasn't.

 

I tested anther constant voltage regulator off anther truck and it shows 12 volts again on both sides.

 

does anybody know how many volts are suppost to be on the out going side of the CVR. I need to know so I can find a reritor to replace my broken one.

 

But yes, it is a pulsing 5v. I'm sure about that, because I made a little modern circuit to provide the 5v. Mine works great. But, it did not fully repair the reading of the gas tank sensor. The trouble is that the little wiper on the the level sensor gets weak. I hear you can bend it back in place to fix it.

 

It does send a pulsing signal, after a couple minutes. The first 30-90 seconds, it remains a solid current. This is so the guages get close to their true reading quicker.
Not sure on the output voltage, but 5v-6v sounds about right.

 

I just read a post the other day about the CVR. Numberdummy listed several part numbers I believe. And someone posted some info about how they made their own CVR out of some Radio Shack parts. It's a real simple circuit and would cost less than $10 to make. I'm sure a search would find it.

EDIT: Found the link!
https://www.ford-trucks.com/forums/7...tage-unit.html