Looking for some help trouble shooting the rear blower motor on an 05 suburban. Currently it will not turn on at all. Ran 12v direct to the motor and it turns on. I was getting intermittent voltage to the resistor so I checked the overhead switch and it had some corrosion on the board. Pulled it apart, cleaned and touched up the solder joints. Checked all Fuses and relays under the hood and they all seem to be working correctly. When testing the relays I can hear and audible click. The resistor is a 3 wire with orange/hot black/ground and purple which i assume is the signal wire from the switch/relays. What voltage should I be seeing from the purple wire on different settings? Anyone have a wiring diagram for the overhead switch? What else is there to check?

 

Wanted to update this in case someone ran into the same problem. Turns out I had multiple issues. 1. The rear ac module failed, replaced it with the updated one. Part number 15185966. 2. The blend door actuator failed as well. Tried replacing with a murray brand. It failed within minutes. Take my advice and just buy the ac delco brand. That was an additional hour of trouble shooting that wasnt needed. 3. I swapped in 3 different blower motor resistors and could not get the blower motor to turn on. I could hot wire it with a lawn mower battery and it would work. Turns out there was a short in the connector at the drivers side kick panel that tried to catch the truck on fire. This was causing a massive drop in voltage to the blower. Sometimes it was fine and sometimes it only had 5v. I decided to just bypass it. BTW RU631 is the correct part number for the resistor if you have the auto climate control. You do have to splice in a new harness. Hope this helps someone in the future.