wiring glitch

[a1coolmom]

This should be a new one to the forum!
when we hook up our Starcraft PU to our TV (98 Toyota Tacoma) and use the battery to run the refridgerator while towing, the gas gauge on our TV goes crazy. It shows way less gas than what the tank actually has. Kinda freaked us out the first time because we knew that towing would reduce our gas mileage but a whole tank in less than 100 miles was a bit much! When we tried to fill  up that's when we knew that it was a glitch. It only happens when using the battery for the refridge., so the obvious source is that wire but why and how? any suggestions from the great forum readers out there?

[tlhdoc]

I don't have a clue.  You are right this is a new one for the board, at least I don't remember this one.

[Tim5055]

OK, lets take this step by step.

Any idea where the 12v + is being taken from for the charge line?

Did they possibley use a fuse tap in the dash?  This may cause a low voltage situation where th guage may read funny.

Ideally, the 12v charge line should run directly to the tow vehicle battery with a fuse as close to the TV battery as possible.

Just a guess mind you :confused:

[topcat7736]

I don't know exactly how the gas guage is wired, but here's my guess.

There's a variable resistance sensor in the tank (operated by a float) and a guage on the dashboard. One side of the guage might go to +12v and the other to the sensor. The opposite side of the sensor would then go to ground. If someone tapped off the wire between the guage & sensor (thinking it was a 12 volt feed line in its idle state), the resistance of the sensor and refrigerator would appear at that point to be in parallel, which would lower the resistance to ground causing your guage to go down.

But, it's just a guess. Your best bet is to do what Tim said & run a separate fused line from the battery to the pigtail connector.