Looking for help troubleshooting a rear defogger that appears to not turn off on my 07 Legacy Wagon with auto climate control and heated mirrors.
A multi-meter on the rear defroster tabs is showing a constant ~14 volts running to the grid lines regardless if the rear defogger switch at the instrument console is toggle on or off. There is voltage the moment the car starts / hits the accessory key position. I might be mistaken but I though the the grid lines is only suppose to have power if the defogger is turned on....
I suspect there might be a short in the line somewhere between the switch and the relay or the defogger switch itself might be bad.
1) The rear defogger relay appears to be good, swapped it with the Horn Relay and it worked fine
2) When the Rear Defroster fuse is removed, the voltage in the defogger dropped to zero, so I think the wiring harness between the fuse box and defogger is probably fine / not shorted.
3) The rear defogger switch functions visually as normal, it lights up when its pressed and also turns off automatically after 15 min.
Note the defogger currently does not work due to massive breaks in the grid that I was getting ready to fix until I noticed this problem.
Thoughts anyone on how to find the problem or test the switch?? Thanks!