Blower Motor Hi Speed

[Daryllawman]

My hi speed switch does not work......where do I start to look. All the other speeds do work.

 

[bmotojoe]

If the 79 is wired anything like the 77 there could be two different possibilities. There is a relay bolted on the (center) right side engine compartment of the firewall. Unplug the connector and check the red wire with a meter or test light to a good known ground. If you have voltage there then the relay is bad or may be a dirty connection. If there is no power on the red wire of the connector then follow that red across the firewall down below the brake booster I think the high speed fan relay fuse is there. It is a 30 amp fuse that powers the high speed fan relay that you just checked.
Now these suggestions are from a 77 wiring diagram so I may be way off here.
Brian
Here is a pic of what to look for:http://www.ecklers.com/product.asp?pf_id=27456&dept_id=1122

 

[gmjunkie]

If the 79 is wired anything like the 77 there could be two different possibilities. There is a relay bolted on the (center) right side engine compartment of the firewall. Unplug the connector and check the red wire with a meter or test light to a good known ground. If you have voltage there then the relay is bad or may be a dirty connection. If there is no power on the red wire of the connector then follow that red across the firewall down below the brake booster I think the high speed fan relay fuse is there. It is a 30 amp fuse that powers the high speed fan relay that you just checked.
Now these suggestions are from a 77 wiring diagram so I may be way off here.
Brian

I'd say your right on track!! Also it could be the fan switch in the console!!

 

[bmotojoe]

Also it could be the fan switch in the console!!

GOOD CALL! I knew I would forget something
To check the switch put it into the high speed position and check the pink wire on the connector plug at the relay. You should get a light or voltage there if the switch is good.
Ignition switch has to be on.
Brian

 

[Bob Chadwick]

The fuse and relay/resistor are much more common than the switch.

 

[Daryllawman]

Thanks , it was a bad connection at the relay.....