Rear defogger inoperative

[Larryjb]

My rear defogger is not getting 12V. Actually, I have measured 14V, then sometimes 5V, and often 0V. I have 12V at the engine compartment fuse. I have not ruled out the relay yet.

Is there anything in between the relay and the connector at the rear glass? I cannot verify that from the factory service manual.

I am suspecting a break in the connector on the rear glass, but I want to verify the relay, and any other connections or modules between the relay and rear glass.

 

[Big Mama]

How about the wires between body and glass? Mine are top left.

 

[Larryjb]

The +12 wire is on the top right, the gnd is top left. There is good continuity to ground. The top right wire provides intermittent 12V.

The tabs on the glass are secure and have good continuity to the grid on the glass. The electrical fault is definitely the 12V supplying the wire.

 

[Larryjb]

I just verified that I can get 12V when the plug is disconnected. However, as soon as I connect the plug to the grid, I get 0V. I am testing from the 12V supply plug to ground.

 

[rockola1971]

I just verified that I can get 12V when the plug is disconnected. However, as soon as I connect the plug to the grid, I get 0V. I am testing from the 12V supply plug to ground.

Module could be sensing an open element (you have a scratch on one of the sides of the grid) .

 

[Doubeleive]

have you tried a new fuse and or relay?

 

[Larryjb]

Checked fuse, tried swapping relays already. I do have an intermittent 12V to the plug wire. I'll pull the lift gate trim later and check the connector in the liftgate.