For some reason, whenever my Jeep gets wet, the gas gauge becomes completely useless. Yesterday (when it was dry), the gas light just came on and I was starting to run low. This morning (a bit damp and sprinkling) I suddenly had about 1/8 more gas in my tank. Then this afternoon (actively raining), I then magically had a half tank. And after I got home and did the gauge diagnostic test to see if it did anything (it didn't), I checked and now had a full tank of gas. Has anyone else had this problem? (Also, feel free to move this if it's in the wrong section)

 

You posted in the right forum.

Maybe condensation is forming in the fuel pump module electrical connector. Crawl under the Heep near the rear axle, and look up towards the fuel tank. You should see an electrical connector for the fuel pump. As well as power and ground for the pump, the fuel quantity circuit wiring goes throgh it. Seperate the connector and look at the pins and pin sockets in both sides of the connector. Look for corrosion and/or evidence of moisture. Get some CRC Electronics Cleaner and spray both sides down. Get some Di-Electric Grease (tune Up Grease) and apply a thin coat around the the rubber seal on the connector and reconnect.

If the pins and sockets were clean then the problem lies elsewhere.

Check back in.

 

Wow, thanks for the quick reply! Since this isn't a life or death problem, I'll probably get around to this problem this weekend. It definitely seemed like an electrical issue, so hopefully what you suggested works-I'll let you know how it goes!

 

At 3.60/gal I like where this is going.
Just siphon it off as necessary to keep the tank from overflowing.

I'm guessing Ken has it right, a bit of dirt in that connector, or the tank ground might become conductive when it gets damp, throwing the gauge off.

 

Well, I figured out the problem! After getting the CRC cleaner and tune up grease, and finally having some free time, I looked under the Jeep and found this:

No wonder my gas gauge wasn't working, the wire was completely disconnected and the other ones were close to splitting too. Me and my dad were able to just splice in some new wire with crimp connectors, wrap it in electrical tape, then two layers of duck tape, and it all works now!

Also, sorry about the late reply- being a high school student with a job doesn't give you too much free time