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      03-13-2013, 04:45 AM   #1
JonEdwards
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E91 Rear window heater failure

Howdy all...

Rear window heater has packed up. Fuse looks OK and I can hear the relay clicking in and out when I push the button on and off. (although looking at the haynes manual, the fuse is after the relay on the heater side, so it would be entriely possible for the relay high power contacts to be dead, but the solenoid is still working)

Googling around, it could be a variety of things:-
Battery condition - car starts fine, despite the cold (there's some kind of sensor system that shuts the ancillaries like the window heater down if the battery is low)
Battery condition check lead failure.
Earth straps between the body and the tailgate, and the tailgate and the rear window.

Now both the earthstraps tailgate to window are broken, but despite bypassing them with a bit of wire - still nothing (how hot should the window get? Presumably I should easily be able to feel the warmth)

Anything else...? Any experiences of this?

Cheers,

Jon
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      03-13-2013, 05:41 AM   #2
verysideways
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Bypassing them with a bit of wire?

How have you done that - have you held the wire there or have you soldered it or what?
Check you check the continuity and/or resistance with a multimeter? That should give you an idea of if/where you have a break in the circuit.
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      03-13-2013, 05:44 AM   #3
doughboy
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Which earth straps? any pics.

And you won't feel any 'heat' from a window strip, they only raise the ambient by a few degrees, they're not heaters!

Last edited by doughboy; 03-13-2013 at 08:44 AM..
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      03-13-2013, 06:04 AM   #4
JonEdwards
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Quote:
Bypassing them with a bit of wire?
The earth straps are bolted on, so I just trapped a piece of wire under the bolt heads. They're a thin plastic coated foil that sort of wraps round the hinges so get flexed every time the boot gets opened. There's a big one that joins the body to the tailgate, then 2 very thin ones that join the tailgate to the opening window.

All the "proper" wiring around there seems very well sealed in, so there's no terminals I can get a meter to without serious effort.
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