General wiring help - 99 Jeep wrangler

[Snoworks]

My rear windshild wiper motor has not worked in a couple of years. I thought I would try and trouble shoot the problem.

The truck is a 99 Jeep wrangler! All the wiring for the hard top goes under the body up to a multi-wire plug. This plug can be disconnected to take the hard top off.

I have the same model truck to reference, it is a 2000 Jeep with a rear wiper.

First I checked the fuse to the wiper, it is ok!
Second I pulled the multi-wire plug to test for power.
-I found the rear dome light feed. It is hot when the door is closed and not when the door is opened.
-I found the rear defroster feed. It is hot when turned on.
-There are two other feeds that are always hot, no matter what I turn on and off. There are a total of six feeds, of which, four run power to certain accessories. (1 - to defogger, 1 - to rear dome lights, 2 - that have constant power).

My 2000 Jeep tested the same exact as above, turning on the accessories, etc. Here is where it gets confusing. When I unplug the wiper motor on this truck and test for power, with the multi-wire plug connected, and the wiper switch on. There are two hot wires out of three. If I turn the wiper switch off, there is only one hot. If I unplug the multi-plug to find out which wire is is powering the 2nd hot at the wiper motor- there is no wire that reads hot when I turn on the wiper switch(other than the two constant hots). Remember that if I keep the multi-plug connected, and dissconnect the wiper plug, I have one wire that has constant power, and one that gets hot when I turn the wiper switch on. I cant trace back the power to the multi-plug because there is no change in any wire when I turn on the wiper switch at this location!

My 1999 tests the exact same as the 2000, except that the 2nd hot to the wiper motor, does not get hot when the wiper switch is turned on!

Any suggestions.


Chuck B.

[wyldman]

It sounds to me like the rear wiper circuit doesn't go through that plug,or maybe you tested it incorrectly.

For the rear wiper to work,you need a constant hot (for parking the wiper motor),a feed from the switch,which should be hot with the switch on,and a ground.Have you checked the ground side ? It sounds like the power feed wiring is OK,so it's gotta be either a bad motor,or a bad ground.

[Snoworks]

Chris, thats exactly why I am confused. Power from the wiper switch to the wiper motor, has to go through the multi-plug. There is no other wiring attaching the top to the truck. I thought maybee there might be some strange way to test it.

If it is a bad ground, I would still get power coming from the wiper switch when turned on?

Chuck B.

[wyldman]

Yes,you will still see power there,but the motor cannot work if it has no ground.You can clip the test light to a hot wire,then probe the ground wire to see if you have a good ground.

When testing the multi-plug for power,did you disconnect the wiper motor plug ? Maybe the power is backfeeding through the wiper motor park switch,so you aren't seeing the switching off and on when you operate the switch.

[Snoworks]

Chris,

The female connector in the multi-plug, feeding power from the wiper switch to the wiper motor was cracked(On both trucks). When you tested for power while the multi-wire connector was disconnected, you would not get a possitive reading, when the switch was turned on(Due to female being cracked, in half). However, when you plugged in the multi-wire connector and tested for power on the back side of the connector it has power.

So I traced the power feed to the wiper switch. I had to take the dash apart to get at it, but I found the problem. The switch itself was broken. I took it apart and found a small spring was damaged(bent). I just replaced the spring and put it back together. Works just like new!:D

Nice to have the wiper working again, and a lot safer for my plow driver operating it!

Thanks again.

Chuck B.