Pontiac Repair: 2005 Pontiac Grand Prix, pontiac grand prix, radiator fans

Question
My Heater was working fine in my car,now the fan wont blow. It s not the heater core as it gets hot and the electronic cluster on the dash panel is fine. One day when it did not work, I thought it mite be a stuck relay,so I tapped on the relays under the hood while the car was running & the heater motor came on, but now it wont come on at all! Can you help,I am not sure which of the 3 relays it is?, the owners manual just calls them 'relays' and doesnt say which ones are for the radiator fans and which one would be for the Heater blower motor?

Answer
Hi Rick!

The relay for the blower is built into the control module for the motor which is under the dash on th right side behind the glove box. it has a harness on it that goes to the motor with a black and purple wire and one harness connector going into the control module. Tap on the motor first with the fan on hi and see if it starts to run. If so the motor is bad if not chances are the blower control module is at fault. You can check the harness at the motor with a test light to connect the test light to the black and purple wires it should light up the lamp bright on hi and dimmer on the lower speeds if s the motor is bad if not like I said it's the control module.
Good luck :)