Cadillac Repair: 79 CDV blower motor, heater blower, blower motor

Question
The blower motor does not come on. It works on high speed if I jump out the resistor. I replaced the resister but still no fan. Where do I start?

Answer
If you look at the very front of the passengers side cylinder head near the front spark plug you will see a single green wire that is connected to a sensor deeply recessed in the head. Either replace the sensor or just remove the green wire and ground it to the body of the vehicle.

If the wire is NOT there look on the drivers side cylinder head on the engine back near the firewall for this single green wire attached to a sensor and replace the sensor or  ground it to the body of the vehicle.

This is your heater blower turn on switch sensor.