Rear defroster

[Rman]

I have an '07 Cobalt (bought it new then) and the rear defrost quit working (switch light is on). The fuse looks good and I swapped relays, still nothing. My DMM showed no voltage at window (one lead on each side terminal) with car running and switch on. I disconnected both leads at the rear window and did a continuity check of the grid on the glass. The grid is good on every line. The Drivers side lead is the pos. The DMM pos to pos lead at window, and DMM common to door frame shows voltage so I know it's get power to the window. I hooked the DMM to both leads while they were disconnected and I get voltage. But when I plug them back in and touch the DMM leads (one to each side at the grid) it shorts out and shows nothing. I cleaned all terminals for good contact. still nothing.

Any ideas?????

 

[Rman]

Voltage

Anyone know what the voltage at the window is supposed to be? I was getting average reading of 8.9v on my DMM, but did get 2 readings of 12+. Wondering if +/- 9v is not enough to heat up the grid?

 

[Rman]

another test

I did some more testing today. With the pos wire attached as normal to the grid terminal on the drivers side, and the ground from the grid on the other side disconnected. I wedged the DMM pos probe in the pos connection. I attached a test lead to the door catch, and clipped the other end to the com probe on the DMM. Sure enough 9v's. but as soon as I touch the DMM's com probe to the ground terminal of the grid, voltage drops to 0. Voltage will stay round 9 until there's a load from the grid. can the grid be bad, even though it passes a continuity test on all lines?

 

[Rman]

Electricians?

Any electricians around here?

 

[Intmd83r]

im clueless sorry ..... bump . try another forum mabey if nobody is able to help you here . i can give you another forum if needed

 

[DOC]

same prob

I have the exact same problem. Any solution pls share.

 

[430747]

pull up the panel in the back under the back window there is a harness plug that melts to getter cut the pink wire form one end and cut the black wire that comes form the window and connect them its on the left sied of the car by the left 9x6