I changed out blower motor resistor pack yesterday. It didn't blow at first but when I put check light to the blower motor it began working. Blower worked fine this morning now nothing. How can I tell if there is something wrong with the BLOWER MOTOR. THE 1234 SELECTOR SWITCH OR THE NEW RESISTOR ??
The fact that the blower started running as you put your check light on the connector there would suggest that there is a bad/dirty/loose contact in that connector at the bower. Try wiggle the cable there while the blower is switched ON and check for loose wires/corrosion etc. in the connector.
Also check fuse 1 (40 A) in the PDC which is the fuse/relay box under the hood and check/swap out the blower motor relay there in the PDC as well.
The Red/Light Blue wire on the Blower should have +12 volts on it relative to ground (chassis). The resistor block interrupts the ground thus slowing down the motor with different values of resistance.
