'99 Heat fan not working

[JoeinMN]

Hi guys,

The heat fan is not coming on in my daughters GP. It doesn't work in any of the speed positions. One thing it is doing that is wierd. When you start the car, the running lights automatically come on, but when you turn the heat fan control to an ON position, a click can be heard in the dash, and the driving lights go out. The lights can still be turned on manually, but maybe it is related to the fan not coming on...Either way the fan doesn't come on.

Can anyone point me in the right direction with this? Is it tear apart the dash time??? I hope not.

 

[rynoman03]

Manual or Automatic HVAC controls? Also it sounds like two things possibly wrong to me...

1.) Blower motor resistor.
2.) Or the switch to the key. Can't remember the actual name but GM routes a main power wire to the thing and sometimes it corrodes and causes problems.

 

[Scottydoggs]

that would be the ignition switch harness.

 

[JoeinMN]

It has manual hvac controls.

So you think the ignition switch harness has corroded and is the problem? With the running lights only? And the Blower motor resistor is the cause of the fan not working? Any insight on fixing these two things?

I figure the wiring harness is in the steering column? How about the resistor?

Thanks for the replies!!!

 

[Scottydoggs]

id start by testing for power before the resistor, its behind the fan motor. if theres no power then the ignition harness should be bad.

if you find power then test after the resistor, if nothing its the resistor, if you have power, then the fan took a dump.

 

[JoeinMN]

Thanks again for the reply. I'll check it out and let you know what I find.