[Efilnikufesin]

Any tips on how to get the in cab climate control fan working on my 1989 Sierra SJ70? My windows fog up every time it rains and I would like to get it working again . It’s never worked in the 10 years I have owned the car. I wouldn’t know where to start .Thanks.

[fordem]

Maybe take it to an auto-electrician?
Maybe check to see if there is power at the fan connector?
It should be a fairly simple circuit - power from the fuse to the switch to the resistor pack to the motor, but if you don't have the electrical experience and the tools, you're not going to get very far.

[Gwagensteve]

Most of the workings on the system (the blend doors, motor plug etc) are readily accessible from under the dash.

I agree that an auto electrician would be a good place to start to ensure there is power to the motor.

The other issues with the system include the heater tap jamming, and the heater core filling with debris which prevents flow.

[Efilnikufesin]

Thanks for the advice , I took it to an auto sparky who got it running again ( a power supply problem as predicted, Thanks folks . ) . I also had the heater assembly replaced due to a bit of a coolant leak in that area , and now it’s all running beautifully. Cheers !