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99 Rear defroster (not a grid issue)

gba88

NAXJA Forum User
Location
PA
Hi Guys,
I've been trying to figure out why my rear defroster quit working. I get power on one terminal of the grid, but not the other -not even sure if that's normal. I cannot see any breaks or continuity issues with the grid itself. I know there are 2 bundles of wires that come out of the top and into the tailgate. I'm thinking a wire in one of those bundles might be broken. Would it be the left or right (or both) that contain the wires that connect to the grid? Any help appreciated.
 
Failure of wires in the tailgate and the drivers door wire harness are common, usually at or near the rubber boot/hinge area. A visual inspection for damaged wires, failed wire splices, and chafed/cracked wire insulation should be your first troubleshooting step.
 
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One connector is 12v the other is ground. When the defroster is on you you should read 12vDC between the two. If you don’t, try checking each one against ground. If you get 12v that way, you know it has a bad ground. If you don’t get 12v, switch your meter to ohms and check against a good ground. If you get 0 ohms on one of the connections, you have a power problem. Either could be a broken wire.


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Thanks for the replies! I found that the boot/rubber thing on the right is for the windshield washer tube and the one on the driver/left side is for the wires. I took the trim off and the hatch cover off yesterday. Holy sh!t there must be about 4 or 5 wires at least that I saw in the bundle where the insulation was cracked and coming off! No idea which was which, but what a mess. I'm going to have to wait until it gets warmer and try to repair all that I can. Thanks for the info about the wires behind the spare...if fixing what I found doesn't work that will be my next place to look.
 
One connector is 12v the other is ground. When the defroster is on you you should read 12vDC between the two. If you don’t, try checking each one against ground. If you get 12v that way, you know it has a bad ground. If you don’t get 12v, switch your meter to ohms and check against a good ground. If you get 0 ohms on one of the connections, you have a power problem. Either could be a broken wire.


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sounds like a quick fix may be just grounding the passenger side to the vehicle. I have 12v on the driver side terminal. I'll have to test again after work one day.
 
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