Hope everyone has a happy new year. My daughter's 1991 Civic wagon has neither heat nor fan working. I have seen questions about later model Civics which said the fan was located on the right side of the dash for these cars. Is it in the same location for a '91? Also, the heater problem (with this weather, it isn't an issue, it's a problem). While the thermostat works, the radiator hoses are hot where they are supposed to be and the rubber hoses leading to and returning from the heater box are very hot, there isn't a speck of heat radiating from the vents. Nada! At some point, she ran over a bump (drives like her mother) and the fan and heat came on temporarily. I've heard, from an independent Honda repairman, that a commutator in the electric motor could be bad and needs replacing. An electric motor repairman said that the wire attachment could be tarnished and needs a shot of white lithium grease.
If either of these fixes worked, should the heat then begin blowing through the passenger compartment?

 

The motor is in the same place, on the extreme right. It has a 2-wire plug plugged into the bottom of it. You don't have to take anything apart to see the plug. With plug still plugged in, turn the key on and switch on high and measure voltage between the two wires in the plug (one probe of the meter on each wire).

If you have battery voltage, the motor is getting power and should be running -- meaning that it is bad. You may need to remove the carpet and/or force something to get the motor / fan assembly out.

If there is no voltage between the two wires, measure from each wire to ground. Zero volts on both means there's no power from the fuse and relay. The fuse is under the hood in the little box next to the battery, not sure about exactly where the relay is, I think it is attached to the fender. Battery voltage on both wires means the ground side of the circuit is interrupted. That involves the resistor, switch, and ground wire.

 

Much obliged, mk378. When she brings it tomorrow, I'll jump on those things.
Jock Ellis

 

My '97 Geo Metro wouldn't run the fan in high, only low and medium. My Porsche 944 runs in everything but low and high. Could the problem be in the control? How often does this problem crop up?