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My rear defog doesn't work

N8N_99xj

NAXJA Forum User
...and I don't know why!

I have voltage at the terminals on the rear window, and when I check voltage to ground going across the grid it smoothly drops like you'd expect on every trace... but the damn thing doesn't clear the window!

My mirrors work fine...

Problem is, I'm the best guy I know for electrical troubleshooting and I'm stumped. Any ideas?
 
I've found the wires partially broken through at the hinge point causing this. They could carry voltage through the remaining connected strands but couldn't carry the amperage required to heat the grid.
 
ah, good idea, I'll check that.

My dome light doesn't come on when the hatch is opened either. Could that be related? The "hatch open" light on the dash does come on however.
 
Well you called it; pulled the trim off, unhooked everything, found one of the wires completely broken. Must have been picking up a phantom ground from somewhere making it look like it was working. Also one of the wires to my CHMSL is almost broken, and three more are looking shaky, maybe one of those is for the dome light? Guess I know what I'm doing this afternoon... I'll friction tape everything well so this hopefully doesn't happen again.

Guess I might as well put some zip ties on the hatch release linkage as well since I've got the trim off...
 
your rear dome light clicks in and out like a button, give it a tap when the hatch is open and your interior lights should come on.
 
Actually it doesn't, the switch is busted (didn't have one originally, got a sound bar from a part out) but doesn't it come on automatically when you open the hatch? If not I guess I'll have to fix that switch.
 
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