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Scott K
Scott K, ASE Master Tech/Instructor
Category: Car
Satisfied Customers: 1569
Experience:  20 yrs exp. Electrical; Driveabilty; Undercar; Airconditioning. Domestic and Foreign.
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The ac blower motor on my 1999 buick lesabre will not shut ...

Resolved Question:

The ac blower motor on my 1999 buick lesabre will not shut off w/out removing the main fuse under the hood even when i turn off the ignition. I haveheard it can be a failing motor along with the power control module. What is the cheapest long term solution and where can I find online manuals for this car?

What about relays or resistors and troubleshooting to make sure?
Submitted: 9 years ago.
Category: Car
Expert:  Scott K replied 9 years ago.

Hello and welcome to just answer,

Do you have auto or manual a/c?

Customer: replied 9 years ago.
Define auto vs manual - I have to set the switches manually - no digital auto control...
Expert:  Scott K replied 9 years ago.

Auto has "degree" temperature settings and typically an "auto" button.

manual has temp setting of C to H or blue to red ands no auto button.

Customer: replied 9 years ago.
Mine is manual - temp is blue to red
Expert:  Scott K replied 9 years ago.

Reviewing the schematic and from your symptoms and descriptions the blower relay (6) is sticking closed. I have included the shcematic and relay location below.


Object Number: 342534  Size: MF

(1)Battery Positive Cable Connection
(2)LH Underhood Fuse Block
(3)Low Speed Engine Cooling Fan Relay
(4)High Speed Engine Cooling Fan Relay
(5)High Blower Relay
(6)Blower Motor Relay
(7)Horn Relay
(8)A/C Clutch Relay
(9)RH Underhood Fuse Block

Object Number: 341759  Size: FS

Scott K and 2 other Car Specialists are ready to help you
Customer: replied 9 years ago.
Just to be more sure of the answer, because I have limited money to spend on repairs...

The blower speed does not respond to the speed control switch in the cab.

The button controls seems to work - they switch between heat, bi-level, vent, max, recirculate, etc. Recirculate does cause the blower speed to increase.

The tempurature responds to the tempurature control in the cab.

The a/c compressor cycles okay.
Expert:  Scott K replied 9 years ago.

With the blower relay stuck closed... the resistor board "which controls blower speed" is taken out of the circuit and blower is stuck on high.

Everything else works because this does not affect other circuits other than blower.

I would tell you to swap with another relay for testing but disconnecting and reconnecting will typically jar relay to "unstick".

The blower relay is about one of the least inexpensive A/C repairs "you lucked out on this one".