Gas Gauge Power

Craigesmith52

New Member
Joined
May 20, 2021
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I have a 1999 tj that recently decided to go swimming. Not a great idea at all. So my dash lights work but gauges will not and I have read several of the posts to get an idea of what it might be. Yesterday I pulled the sending plug off of the gas tank to see if power and/or ground signals are there. When I pulled it the low fuel light came on which tells me the wire is still sound and that light has come on before when I get low on fuel. Wouldn't the gas level signal then still be intact and something else is the issue? If the low fuel signal is sending back information then wouldn't that mean that the ground wire is good? Thanks
 
How long has it been since the swimming trip, and exactly how deep did you go? It may just be a function of letting the thing dry out, especially the connections at the PCM.

I don't know the difference in logic between the light & the gauge because the wiring diagrams only go so far, but the sending unit talks to the PCM, not the instrument cluster. The PCM reads the data from the sending unit & controls the gauges & lights on the IC via your twisted pair CCD data bus. There are a few exceptions like the seatbelt & transfer case lights which are wired directly to the IC, but the sending unit info goes to the PCM.

If none of your gauges are operational I'd be looking to the PCM. Take the connections off, have a look, see if there's still water in there from your adventure.
 
First check the all fuses in the fuse block behind the glove compartment.
Then check the three 32 harness ECU harness connectors pins and clips inside the harness connector and ECU receptacles for greenish or greyish oxidation. Clean with plastic safe contact cleaner that can be purchased at Walmart. Then firmly snap the harness connectors into the ECU receptacles.