Heater BLower Motor

Suburban Guy · February 11, 2005

I'm still trying to figure out the frtont 4WD actuator, but thats another story.. However, I now have a problem with the front heater blower motor. It wasn't working at any speed so I yanked the blower motor out and benched it...worked fine at a straight 12 volts (off the battery). Plugged it back into the vehicle, though not installed (just dangling there) and it worked at all speeds EXCEPT high. In the high(est) speed the voltage goes bye bye...zero, . I pulled the resistor pack, and they (windings and resistor) all "look" good but due to location I can't get it out to test it (it's really wedged in there!).

Whats the likely hood that the resistor pack is flakey? I ran the motor on the bench for quite a while and it never slowed down or got hot.

Ideas?

Wendell

neonbee · February 11, 2005

Just replaced one in my wifes van..............same problem.

Turned out to be the resistor going for a cr@p.

Good luck,

~Neon~

Suburban Guy · February 11, 2005

Iv'e come to the conclusion that it's the motor. When It doesn't work I rap it one and it goes again. Connections are good so i suspect that it's a crapped out motor.

Other ideas???

sjspor · February 11, 2005

You don't list the year of your truck, but the NBS trucks have a blower resistor that fails, usually you loose one or two speeds of the fan first. I know on my truck the green covering was peeling off the resistors so that may be a sign too. Anyway, the resistor is screwed into the blower housing, where all the wires go. It's a 15 dollar part.

71GMC_3/4T · February 11, 2005

The resistors are not used for high speed. They are only for the lower speeds. For high, there is a relay, usually mounted in the same area near the motor. Most likely you have an intermittant ground on the relay, tighten the screws, it has to be connected to chassis to work. That, or you have a bad relay, but if it works sometimes that probably isn't it.