wiring problems

[Bagoneer]

O.K SO I HAVE A FEW WIRING PROBLEMS, First the rear glass will not go down, hot wired the motor and it works. how do i test the switch or any other ideas as to what the problem could be. Secondly the fuel guage does not work, The gas tank is out and I wold like to fix it now how do i test the sender? or any other ideas? HELP!!!!!!!!!!!!!!!!!!!!!!!!!

[Lindel]

First off, welcome to the forum, and I/we need to know a little about your Jeep, before we can give accurate advice.

Since you've determined the motor is good, have you checked all the fuses, and have you checked both switches, you have the one on the dash, and there's also one at the door.

If you have a volt/ohm meter, you can do a resistance check on the switch, and see if it operates that way, or get a test lamp (12v bulb with wires attached, basically. You can get one for a few dollars, or make your own), and use that method. Depending on the year of your truck, the switches might be wired independently of each other.

On the gas tank, since it's out, the best way to test is with an ohm meter. You can pick up a fairly decent digital one for about $20 at most hardware stores, or I've seen some at Wal-Mart. Again, depending on the year, you will have different readings. The older rigs, 85 and earlier, have stewart warner senders, and will measure between 24, and 333 ohms IIRC, and the newer rigs, from 86 to 91, will have GM senders, and will measure between 0 to 99 ohms. I don't recall what measurements represent what, off the top of my head, and I don't have my manuals in front of me. I'd suggest either the TSM for your truck, or a Haynes manual, at the very least.

[Jeepzilla]

Most fuel guage problems are poor ground. To test the sender, set ohmmeter to low scale. Put probes into the connector holes. If you have the sender in your hand, move the float up and down. The resistence should change from 110 ohms at full to 55 ohms at half to 1 ohm at empty. Readings other than these mean faulty sender--replace.

[Bagoneer]

Sorry the waggy is an 81, will the switch in the tailgate work if the switch on the dash does not? My truck has a plastic tank, Will a sender from a steel tank work in it as I have a new one of those in a truck i just bought? Thank you Jamie

[Lindel]

I do believe that the tailgate switch is wired up independently, but another thought comes to mind. If you can get the window down, and the tailgate open, there is a safety switch on the drivers side of the tailgate, near the top. It kind of looks like a J, and if it's bad or is misadjusted, then the rear glass won't move. It's supposed to keep the glass from moving with the tailgate down.

Try pushing on the top of the tailgate, on the driver's side, while someone else operates the switches (either front or rear). Or, get the tailgate open, and bypass the safety switch, and then see if the other switches work.

[Lindel]

The sender in the steel tank might work, if the guages look the same in the vehicles. That is, as long as the instrument panels are the same.

You should be able to get to the sender in your wag fairly easily, by using the access panel under the rear seat, and carpet. It'll be riveted in, but with some careful effort, you can drill the rivet out.

Good luck with the gas gauge!

[SandHog]

I found that the tailgate safety switch inside the tailgate on the drivers side was the cause of my rear window failure in not 1, not 2 but all three GW's I have owned. Dangerous as it sounds (I know...ooooooow danger) I just took it out and by-passed it. All this does is allow the window to be operated when the tailgate is open. Thats my experience. Good luck.