Sooo..
A continuity check will determine if a wire is broken correct?
I discovered that I have a broken "element" wire on my 2004 by seeing that when I turned on the defroster that it wasn't defrosting/clearing along one of the wires, didn't think it was to much of a problem since after several minutes the windows heated up enough to clear the entire window.
Glad I just happen to see this topic, I won't be using the defroster any more so I don't risk losing the window!
OP and others sorry for your misfortune but thanks for posting, ya'll most likely save others the cost of their rear window, I know you have saved me the cost, THANK YOU!!
It's an easy fix, any auto parts store should have the repair compound. FSM recommends voltage check not continuity. It's a resistor. Read last post on previous page.
We sure that the issue is uneven heating due to damaged lines? I was more curious about why some of the connectors look very burnt.
We sure that the issue is uneven heating due to damaged lines? I was more curious about why some of the connectors look very burnt.
Completely agree, the pics of some of the connectors look very melted, which tells you, in those cases, it wasn't likely that a defroster strip related glass temperature variance that caused the failure.
My guess is that the connector corrodes due to moisture, creates a short, arcs at the plug which causes a lot of heat quickly and boom, broken back window.
I cleaned, inspected, and re-greased the connection on mine while I was replacing the rubber on the hatch button. It is easy to access and cheap insurance imo. I would also think that replacing the rear window seals as necessary to keep moisture out of the tailgate would help also. Too many car owners seem to overlook those as simple and cheap maintenance items. :bigok:
If it was corroded there would be more resistance = lower voltage to wires so less heat at window. Arc would be shorted to ground before circuit so much less or no current to wires/ heat. Those plugs look pretty standard for older plastic connectors that carry current regularly, don't think that's the issue.
We sure that the issue is uneven heating due to damaged lines? I was more curious about why some of the connectors look very burnt.
I was referring to the pics like the ones seen in this thread (melted plugs and burned connections): http://www.toyota-4runner.org/4th-gen-t4rs/73590-rear-windshield-shattered-morning-4.html
that is not standard.
Not to say the other issue isn't legit, but we have definitely seen melted/shorted/burned/arc'ed plugs and connections as well.
If it was corroded there would be more resistance = lower voltage to wires so less heat at window. Arc would be shorted to ground before circuit so much less or no current to wires/ heat. Those plugs look pretty standard for older plastic connectors that carry current regularly, don't think that's the issue.
Not sure about corrosion, but high resistance will lower voltage and increase current (which when the result of resistance will create heat).
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That's the second picture of connectors I have seen regarding blown rear glass and that burn mark where the metal is peeling off the glass is odd. It doesn't look corroded, but that's probably where a heat spike occurred and most likely caused it to shatter?