95 Suburban -- Blower motor "high" won't work

[bigeds57]

The "high" speed setting on the front blower motor does not work. The first three work just fine -- this goes for both heat and A/C and is just on the front blower motor. At first the high speed would work intermittently, but now nothing. I've been told that there is a seperate relay or resistor as part of the high-speed control circuit that has failed and is pretty easy to replace. Once I know the problem, I'm pretty good at attacking the problem, so anyone with specifics would help tremendously!!
Thanks,
Ed

[bigeds57]

I guess no one out there has had this problem -- or at least know how to fix it. Someone please helppp!!

[brooster]

This should be caused by a relay. All of the lower speeds are routed through the resistor block. High speed is accomplished by sending full 12 volts to the motor.

This is not usually done by the switch as it is too weak to handle the current. Rather the switch closes the high speed relay. The relay sends the current from its source to the motor.

Where's the relay? Don't know. The batteries for my shopkey/PDA are dead. I would suspect in the relay box on the drivers side or the firewall on the passenger side.

[bigeds57]

Brooster -- Thanks for your help. As long as I know it's the high speed relay, I'll get one at the dealer and they should be able to help with telling me the location. I just didn't want to start buying parts blindly as a way to fix the problem.

[michelq]

high speed relay located behind glove box

[Big Sim One]

I had this problem, it turned out being a burnt pin in the connector that attaches to the back of the fan speed switch. GM has a kit that allowed me to only change the defective pin in the connector. Hope this helps.

[PMCF]

PROBLEM IS THE BLOWER RESISTOR...LOCATED BEHIND GLOVE BOX DOOR, HIGH AND LEFT (NOT OVER AND LOW BY THE BLOWER). LOOK ON TOP OF HVAC DUCTING. REMOVE BRACKET THAT HAS A RELAY ATTACHED, UNPLUG AND PUSH ASIDE WIRE CONNECTORS. RESISTOR MOUNTED TO TOP OF DUCT BEHIND THESE WIRES YOU REMOVED. MOUNTED WITH TWO 5/16th SCREWS DOWNWARD....VERY TIGHT TO WORK ON AND REMOVE. PRACTICE REINSTALLING WITH THE OLD BEFORE YOU TRY TO GET NEW ONE IN PLACE.