I recently bought a 90 silverado that was not taken care of. When I purchased the truck, not a single bulb worked in the vehicle. Im talking front lights, tail lights, courtesy lights, nothing. The AC control module would not turn on and neither would the radio, So, the first thing I did when I got the truck home was removed every piece of the interior except for the AC housing and blower motor housing so that I had access to the fuse block and the wiring hareness. After a day of tracing wires, I have every bulb working as it should (not counting the radio). I am now trying to tackle the AC system or what is left of it.
Just a little background, the truck has a non working AC compressor and the condenser was cutout of the vehicle. The first thing I addressed was the AC control module in the console. Watched a youtube video and soldered the components mentioned in the video. That control module will NOW turn on. Not sure if it is functional or if it is just powered up. I'm starting on the inside components of the truck. Right now the blower motor will not run in the vehicle. I bench tested all the relays with a multimeter and they test as ok. I took the blower motor out and bench tested it. The blower motor will run on the bench. I put the blower motor back in the truck, powered it up with a power probe III and it will turn on and run but I cannot get the blower motor to run without the power probe. I thought the relay might be bad even though it bench tested fine. Replaced all 3 relays there in the glove box and the blower motor will still not run. So, my next move was to jump the relay. I took a wire from the 30 pin to the 87 pin and the blower motor kicked on. Put a multimeter on the wire that runs from pin 87 to the relay and there is no power getting to pin 87 where it connects to the blower motor resistor. I didn't know if this might be a control module issue or an issue with the blower motor resistor or both?
Any of electrical experts have any thoughts or suggestions, I'd love to hear them. Thanks in advance for any help.
Just a little background, the truck has a non working AC compressor and the condenser was cutout of the vehicle. The first thing I addressed was the AC control module in the console. Watched a youtube video and soldered the components mentioned in the video. That control module will NOW turn on. Not sure if it is functional or if it is just powered up. I'm starting on the inside components of the truck. Right now the blower motor will not run in the vehicle. I bench tested all the relays with a multimeter and they test as ok. I took the blower motor out and bench tested it. The blower motor will run on the bench. I put the blower motor back in the truck, powered it up with a power probe III and it will turn on and run but I cannot get the blower motor to run without the power probe. I thought the relay might be bad even though it bench tested fine. Replaced all 3 relays there in the glove box and the blower motor will still not run. So, my next move was to jump the relay. I took a wire from the 30 pin to the 87 pin and the blower motor kicked on. Put a multimeter on the wire that runs from pin 87 to the relay and there is no power getting to pin 87 where it connects to the blower motor resistor. I didn't know if this might be a control module issue or an issue with the blower motor resistor or both?
Any of electrical experts have any thoughts or suggestions, I'd love to hear them. Thanks in advance for any help.
Last edited:
