99 TJ rear defroster help!!!

dvibbert

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Feb 23, 2016
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32
Location
Maysville, KY, USA
I am sure this has been covered but I couldn't find the answer. I have a 99 TJ that was originally a soft top model. I purchased the harness for the rear wiper/defroster that goes from the dash to the rear. I also purchased the harness that had the switch plugs for wiper/rear defrost. I have the wiper working perfectly fine. I can hear the relay click but I still have no power to the rear defroster. What am I missing????
 
Does the wiper and defroster work off the same fuse?..if not you might have a blown fuse.(just an idea) :)
 
Do you have the factory wiring diagrams in the FSM? It's worth looking at them just incase, because you could have a missing ground wire or something like that.

First thing you should do is hook up a test light. Does the wire to the rear defrost get power when you flip the switch on?

That will tell you a lot right there.
 
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I used a test light with no power results. I clipped ground on one terminal and pointer on other terminal. Nothing. I tried a separate ground and checked both terminals . Nothing.
 
I started this and then had bigger issues to deal with. I still haven't figured this out. When I push the rear defrost button I hear the relay click still but no light and no function. I do not have any power on either side of the defogger fuse behind glove box. If I put power to the fuse by jumper wire the light comes on and I have power to the back defogger
 
I am sure this has been covered but I couldn't find the answer. I have a 99 TJ that was originally a soft top model. I purchased the harness for the rear wiper/defroster that goes from the dash to the rear. I also purchased the harness that had the switch plugs for wiper/rear defrost. I have the wiper working perfectly fine. I can hear the relay click but I still have no power to the rear defroster. What am I missing????
If you want proper help I can assist, but I'm going to need quite a few pictures. Did you route the wires to the relay box or is the relay just sitting somewhere under the hood? Is this a used wiring harness you sourced or a new kit? Definitely sounds like a relay failure, have you put a multimeter on it to test constant ground and quality of power on the relay? The relay click is caused by the relay turning off and on rapidly usually a point of failure in the system. Help us help you, get us some pictures of whats going on :).
 
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I replaced the harness from under the driver side back to hardtop plug, I also replaced the harness from driver side that included the switch harness. Both were OEM used harness'. The wiper works perfectly. When I push the defrost button the relay clicks once. It doesn't click off and on rapidly. I checked the relay output and only have power on one post/terminal. I would assume that when the switch is engaged the relay should supply power thru the fuse box under the dash. I have no power on either side of the fuse under the dash for the defogger