I have seen many ask why a 66-67 gas gauge does not work. Other than the obvious sending unit. Oh and the ground wire at the sending unit being truely grounded. ( I always use those teethy washers on all grounds) Here is a possible cause. The plug in at the printed circuit can have broken prongs. I have seen this in almost every other one I take apart. I am sure a good person with a soldering gun can repair this. I was lucky to have a good printed circuit. I have also found that bypassing the plug works if you are not going to pull the dash. (see picture)

Only three wires feed the fuel gauge: 12volt keyed, ground , and the sender.

Pic 1 is the printed circuit plug with three prongs missing
Pic 2 is the plug in with three prongs in it
Pic 3 is a good printed circuit
Pic 4 is wires bypassing the plug in


Here is a few images of the prongs broken. and a good printed circuit plug in.

Hope this helps some who are trying to figure it out.

Larry

 

Excellent info! Thanks for that. It might explain why my fuel gauge worked for a moment after I repaired the ground, and then quit again. Part of the issue with mine was the previous owner had removed the fuel tank and managed to break the ground wire off the sending unit. Here are some pics of how I fixed that end. You can see in the first picture that the ground lug is almost indistinguishable from the rest of the surface rust. The second pic shows the rust scraped off a bit. Third pic shows the female connector that fits on the ground lug perfectly!



IMG_20150622_185740083_HDR_zpsex9a2kfn.jpg

IMG_20150622_185752956_HDR_zpsg0q5v68w.jpg

 

I've actually just recently started messing with my fuel gauge. I took the sender out cleaned it and confirmed it was operating properly and still doesn't work. I'm going to look into this on my car next time I mess with it

 

Broken pins can be repaired by using 2mm screws obtained from model shops. Insert screw through opposite side of cct. into broken pin. Try screws that are about 1/4 inch long.

 

DING DING DING We have a winner^^^^^^^^^^^^^^ I have been using #1 sheet metal screws for years to repair/tighten loose pins. If I have a board with completely broken off pins,I toss it and find another board.

 

Rocket Olds
you asked me about this thread and I just found it. hope it helps.
Larry
lemoldsnut@aol.com
541-815-4363

 

 

Mine quit working because it needed to be lubricated. Same for the speedometer. Paid a speedometer shop $200 to learn that, so I thought I'd save someone else the money.

 

Similar fix here: https://classicoldsmobile.com/forums...uit-board.html

 

Was just asked about this again. SO, thought I would post on it to put it back up on the top.

Hope it helps someone
Larry

 

Good info, thanks. In picture 4 with the wires bypassing the plug, can you please identify which function each wire is? That would help me with my testing. Thank you, Joel

 

As your sitting in the car looking forward. Bottom is ground, upper left is keyed 12 volt. Upper right is sending unit

 

Got it. I just tested by applying 12v+ to the upper left and the gauge now works!

Thank you!