[8my$]

So I have a 1968 Firebird convertible factory air. Still has A/C box in the car, but no compressor. The blower motor only goes on low. I have it out and the switch. The switch seems to progress properly, but no change of volts at motor. When I move switch to high I can hear a relay click on top of A/C box. Not sure what the relays do? Any help? Thanks

[gtofreek]

The fan speeds are controlled by a resistor that bolts into the air box. The high speed blower is controlled by a relay[probably what you here clicking on]. My guess is that the resistor is burned out on the medium speeds, and the high speed relay has no power feeding it. The high speed relay has a main power wire feeding it that then passes on to the fan motor when the relay is activated. Find that relay and test it with a test light to see if there is power on the heavy red wire. If so, then check to see if another terminal gets power when you turn the fan switch to high. If so, you should get power out the purple wire[IIRC] which goes to the blower motor, providing the relay has a good ground also. You can also test the resistor by just probing the individual wires that go to it, checking for power on a different wire with each click of the fan speed switch.

[8my$]

Thanks for the reply.Just what I needed. Chasing wires right now. I'll post the findings.

[8my$]

So the power wire to the high speed relay is not hooked up. Where should it be connected to? Thanks