whats going on with my gauge???

[studie91]

just picked up a 91. the headlight switch was broken so i replaced it with a new one. well now im having problems. the fuel gauge worked the whole way home. after i replaced the switch the fuel gauge is being funny. when the headlights are on it reads all the way empty, with the headlights off it reads above full..has anyone dealt with this before? is a ground issue??

[CumminsPower59]

First, Welcome to 1stgen.org!

Second, Sounds like there is a short to ground in there somewhere, check the wiring and the like. These things are known to have some sub-par wiring from the get-go.

[studie91]

cumminspower59 thank you for your quick reply! what do you mean by "check the like"? i almost out of place to check? i dont know if i should look on the headlights side or on the fuel gauge side?

[CumminsPower59]

Do you have any wiring shematics to reference off of? Almost sounds like it's in the cluster or something as it goes on the fritz when the lights are on/off.

[studie91]

the truck came with a FSM and a friend and i spent the most part of the afternoon tracing wires but had no luck. i do have a a few gauge clusters lying around i may replace the fuel guage. or just switch out the cluster..would a gas motor cluster be the same as a diesel? i never heard of the problem before..i even swaped out the diesel message center..im so lost on this!!

[CumminsPower59]

I wouldn't know on the clusters, I am sure someone will chime in soon enough. BTW, you are a leg up on me, you got a FSM, I don't. I usually spend considerable time scouring the internet for something to reference off of. Is it JUST the fuel gauge going crazy? Everything else ok?

[studie91]

well, it was. i just went out to the truck and turned the lights on. all i have is head lights. no gauge lights, no radio, and no marker or tails. everything was working exept for the fuel gauge this afternoon. bad ground maybe??

[CumminsPower59]

Ground, possibly. I think that there maybe fuseable links in there somewhere too...not 100% sure though. If I had a FSM manual in front of me I could make a better guestimation. Did you search for some older posts in this section? I think I have heard of the "running lights not working" before...

[93flatbed]

well, it was. i just went out to the truck and turned the lights on. all i have is head lights. no gauge lights, no radio, and no marker or tails. everything was working exept for the fuel gauge this afternoon. bad ground maybe??

Isn't all of that on the same fuse?

[studie91]

figured it out! thanks for all the help! it took all day but we finally got it fixed. found that the black/yellow running lights wire had a bad spot in it right at the firewall. so we cut out the bad part of the wire out and every thing now works! the fuel gauge is a bit sticky and when i was filling it up with fuel it wasnt moving so i gave the fuel tank a nice kick and it moved all the way up. i also fixed the odometer so i know for sure if its accurate or not. thanks again.

[CumminsPower59]

Good deal! I checked my speedo using GPS and with the help of a friend of mine who is a local cop since their radar is calibrated. Got it so it's spot on at 55mph, a little fast at slower speeds and a little slow at faster speeds...good enough for me