Chevrolet Repair: 92 chev s10 blazer elec problems!, electrical diagnosis, s10 blazer

Question
My blower moter quit working intermittently for about a week. i later noticed when my head lights are on and i turn the heat or ac on, my headlights dim and the blue highbeam light comes on. if i turn the heat to "off,"  and turn my lights on they are fine, but when i turn them off, i hear a short buzz from under the dash by my feet. what could this be and how can i fix this? thx!

Answer
It sounds like you have a short circuit that is affecting other components.

First I would disconnect the HVAC blower motor. Recheck all the accessories. If they all operate normal, then the blower motor is defective and shorted.

If problem still acts up with blower motor disconnected...I would then try disconnecting the HVAC blower relay (usually on back firewall near blower motor). If everything is ok now you either have a defective relay, shorted blower resistor, or short circuit in the wiring that goes to the blower relay. You'll have to have some electrical diagnosis skills to repair.

If problem still acts up with all 3 items disconnected, then the entire circuit needs to be diagnosed. May be better taking it in for repair for that.