rear defrost question

[JWX]

ok, I think I have a bad ground or something in my hatch. when I turn on my rear defrost the volt gauge goes down slowly and stops at about 12-13 volts and no amount of reving will bring it back up. thats only with that and the radio and the engine runing, if I have the the headlights and stuff on like this mourning the volts ran about 12 or so all the way to work and when I got there I turned off the rear defrost and it came back up. and the bottom three or four and about two lines down for the top don't work, but the rest do I checked the grid with a test light and there getting power but not doing anything. what should I look for?

(and yes for those wondering I have been driving it a lot lately)

[EmmCeeBee]

The defroster sucks a LOT of power (even with a few rows missing). It sounds normal -- that when you turn it off, the battery voltage goes up.

 

You probably have a weak electrical system, it should hit 13+ volts when you rev it. I'll let someone else help with that, I don't know 'nough 'bout sick alternators or voltage regulators.....

 

Defroster lines (the rows on the rear window) are easy to scratch, and that's what kills a line. A scratch can be all but invisible. I can't imagine anything else causing a few of the lines to drop out. Clean the window (c-a-r-e-f-u-l-l-y) and inspect them with a magnifying glass. Parts stores have a dab-on fixer, that completes the electrical circuit. Some other thread here today mentioned that fix.

 

-- Mark

[JWX]

so is this a weak elec. system or normal

[JWX]

bump

[Meeky Moose]

i had this sorta prob after i swapped teh engine in my ahtch..

 

clean, and tighten the ground that goes from the front of the engine to the body over by the battery.. thats what my prob was..

 

if that doesn't help.. your alt just might be gettin weak..