Pontiac Repair: Intermittant AC blower on 1996 Bonneville SE, mortor, high position

Question
My sister's car was only working on high (position 4) most of the time. I could trick it to work on the lower three positions by switching back and forth. Now it only work sometimes in any speed.  She says somthing about a replaced burned thing (relay I guess) being replaced with a used one by a mechanic.

Answer
Hi Al:

well it could be a few things. The blower mortor uses a part called a resistor and that is what gives you the lower speeds. The resistor is located in the heater case under the hood. That could be bad or the relay which you said you changed? Was it the same part # as the one you took out? the last thing could be the blower switch it's self in the control head.. Of all the parts it could be the most likely cause would be the resisitor or the relay. Good luck :}