Wired
Junior Member
- Joined
- Dec 4, 2014
- Posts
- 7
- Reaction score
- 1
- Location
- Everett, WA
- First Name
- Kyle
- Truck Year
- 1979
- Truck Model
- K30
- Engine Size
- 5.7L 350 V8
Recently the blower motor on my 79 K30 (no A/C) randomly stopped working without notice. I decided to start at the motor itself and work through the system and it is stumping me. I'm hoping some of you guru's can help, as my experience is mainly from modern GM vehicles.
First I checked the motor. I supplied it 12v from the battery while it was still in place and is spins fine. I was also able to operate it with a 12v duracell.
Next I measured voltage from the lead that connects to the blower motor terminal. It reads anywhere from 8-10 volts when the truck is on, but does not power the motor when I plug it in. Voltage would stay constant regardless what setting the speed switch was set to.
The resistor is plenty rusty on the inside, but still has continuity between all appropriate connectors.
Next I took the fan speed switch off and took it apart. It was dirty but I cleaned all the contacts and check continuity; it was fine.
I then measured voltage coming from the brown wire that leads into the fan speed switch and plug. It would read 8-10 volts. But get this, as soon as I plugged in the blower motor, the voltage would drop to 0. This made me assume a circuit breaker was tripping (in addition to it only being 8-10 volts instead of 12+).
I checked the heater/A/C fuse and it was fine (20amp)
To top it off, while working on this problem, the wipers stopped functioning. Fuse is fine, and power is getting to the wiper motor.
What does it take to kill a gremlin? I can take photos of anything anyone would need to help solve this. I plan on checking continuity between the resistor and the noise suppression coil to see if a wire is corroded/barely contacting as another member here suggested.
THANKS for any help you guys can give.
First I checked the motor. I supplied it 12v from the battery while it was still in place and is spins fine. I was also able to operate it with a 12v duracell.
Next I measured voltage from the lead that connects to the blower motor terminal. It reads anywhere from 8-10 volts when the truck is on, but does not power the motor when I plug it in. Voltage would stay constant regardless what setting the speed switch was set to.
The resistor is plenty rusty on the inside, but still has continuity between all appropriate connectors.
Next I took the fan speed switch off and took it apart. It was dirty but I cleaned all the contacts and check continuity; it was fine.
I then measured voltage coming from the brown wire that leads into the fan speed switch and plug. It would read 8-10 volts. But get this, as soon as I plugged in the blower motor, the voltage would drop to 0. This made me assume a circuit breaker was tripping (in addition to it only being 8-10 volts instead of 12+).
I checked the heater/A/C fuse and it was fine (20amp)
To top it off, while working on this problem, the wipers stopped functioning. Fuse is fine, and power is getting to the wiper motor.
What does it take to kill a gremlin? I can take photos of anything anyone would need to help solve this. I plan on checking continuity between the resistor and the noise suppression coil to see if a wire is corroded/barely contacting as another member here suggested.
THANKS for any help you guys can give.