Auto Air Conditioning & Heater Repair: 1990 buick Lesabre not blowing heat or air, volt circuit, buick lesabre

Question
I have a 1990 Buick Lesabre with the two horizontal slide rails and 1 vertical fan 4 speed heat/AC switch. I have no air blowing at all..I know the actual heat works...because if I drive on the highway with all heater controls on I do feel warm air...but it wont "blow" out regardless of the switch position (hi or low).  One of my brothers says its my heater fan blower motor....and my other brother says its probably just the switch... but neither will take the time to check...how do I do this? can you help?  I'm in Minnesota and it's getting cold!  Thank you

Answer
If you have NO blower operation at ALL on any fan setting speeds your problem MIGHT be the blower motor but could be the blower motor relay.

If you own a 12 volt test light we can do some simple tests since this is a 12 volt circuit.

This test is ONLY if you have NO BLOWER operation on ANY speeds.

Attach the test light to the PURPLE WIRE at the blower motor. While watching the blower motor try all the various heat and A/C settings and blower speeds and see if the test light illiminates. If it DOES, Check to be sure that the  BLACK ground wire also attcahed to the blower motor housing is securely grounded to a metal surface.

If the GROUND is OK then replace the blower motor.

If the test light does NOT illiminate in any settings, Locate the BLOWER MOTOR RELAY mounted on the firewall near the blower motor or mounted at the realy panel near the right side head lights.

The relay will have the following wire colrs to the relay socket:

ORANGE.
DARK BLUE with a WHITE stripe.
RED.
BLACK
PURPLE.

If you can't find it, Buy a NEW relay at any parts store so you will know ans see what your looking for.

If you need additional help, Let me know.


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