Hi guys. I'm helping my buddy with his 2001 4x4 LS Blazer. His low fuel light has been stuck on along with showing an empty tank all the time for months. We just swapped in a new AC Delco pump/sending unit and we were rewarded with the same results. Yay us! I need some assistance trying to figure this out. Can I just splice in a ground on the small black wire at the sending unit connector and connect it to the frame? Not sure where to go next. Any help is appreciated.

~Magman

 

Your on the right path. Thick wires are for the pump, thin wires are the gauge. Try following them. may be an issue with that

 

Well, I did some more searching and it sounds as if I need to trace the small purple wire that goes from the sending unit to the VCM. From what I gather, if it was a ground issue, the tank would read full or erratic. Since mine is pegged on empty and NEVER changes, it sounds as if the signal from the sender is shorted to ground. Any tips where to read out wires to help narrow this search down? Thanks.

 

Success! I fixed it tonight. After reading out the connector at the plug, with the key in the run position, I had 5Vdc on the purple wire, good ground on the larger black wire, but no ground on the small black/white striped wire. I spliced both the small black/white striped wire and larger black wire together, and ran a new ground to the frame and the gauge/fuel pump both worked!

My question now is, what should I do with the two wires I cut; the smaller black/white striped wire and the larger black wire I cut on the vehicle wiring side, known as the reference ground? Should I just splice them together? Should they be spliced together then grounded at the frame? Should they be grounded separately? Right now they're just cut and laying loose. I just don't want to cause any other electrical problems. I would certainly appreciate some guidance, as I have very minimal electrical knowledge. I'm learning through the search feature now...LOL!

 

Glad for the success, thanks for updating your post!

 

Exactly which wires did you look into and where were they located