Taemian
06-24-2015, 11:58 AM
So my fan motor stopped working (no blowing a/c or heat) and I started the troubleshooting process.
Checked fuses in car (103 and 301), and underhood 40A fuse and relay. Everything was good. Did a self test on EATC to see if it was the actual "wheel" switch on the panel, but no faults were shown.
Hooked the fan motor itself up to a small 12v battery (6A) via some jumper wires and it fired right up. So it MUST be the BCM, right?
After grabbing a spare BCM from a wrecked MM (good to have 2DMax as a friend with 3 MMs plus a parts car!!) I plugged it back in.
And nothing. The BCM has a plug that it connects into which has 5 pins-- 3 small ones in a row, and two big ones in a row. If you jump the two big ones (bypassing the BCM) the fan motor should go full blast, but I got nothing. About 1 minute in this video it is shown:
https://www.youtube.com/watch?v=rHvpoNzxemc
Since the plug is almost impossible to take off until you actually remove the BCM, I just used a battery to test the motor directly.
The problem was somewhere in the harness. When I tried to jump the terminals, nothing. A test light showed no power to either side of the big two. Oh boy, wiring harness problem....
Just to completely confirm the problem, I made a wire with two spade connectors and tried to plug it in. When I made contact, there was a small spark and then constant power came back.
Moral of the story? Check, check, double check, triple check and repeat! Sometimes there is a ghost in the machine...
Checked fuses in car (103 and 301), and underhood 40A fuse and relay. Everything was good. Did a self test on EATC to see if it was the actual "wheel" switch on the panel, but no faults were shown.
Hooked the fan motor itself up to a small 12v battery (6A) via some jumper wires and it fired right up. So it MUST be the BCM, right?
After grabbing a spare BCM from a wrecked MM (good to have 2DMax as a friend with 3 MMs plus a parts car!!) I plugged it back in.
And nothing. The BCM has a plug that it connects into which has 5 pins-- 3 small ones in a row, and two big ones in a row. If you jump the two big ones (bypassing the BCM) the fan motor should go full blast, but I got nothing. About 1 minute in this video it is shown:
https://www.youtube.com/watch?v=rHvpoNzxemc
Since the plug is almost impossible to take off until you actually remove the BCM, I just used a battery to test the motor directly.
The problem was somewhere in the harness. When I tried to jump the terminals, nothing. A test light showed no power to either side of the big two. Oh boy, wiring harness problem....
Just to completely confirm the problem, I made a wire with two spade connectors and tried to plug it in. When I made contact, there was a small spark and then constant power came back.
Moral of the story? Check, check, double check, triple check and repeat! Sometimes there is a ghost in the machine...