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Ask Don 'Mo Lurch' Your Own Que...
Don 'Mo Lurch'
Don 'Mo Lurch', Cadillac Technician
Category: Cadillac
Satisfied Customers: 20901
Experience:  GM, Cadillac Cert., Heavy Line Mech, Race Shop Owner, Mobile Electronics.
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98 Cadillac Eldorado having issues with the blower motor not

Customer Question

98 Cadillac Eldorado having issues with the blower motor not working. The plug going to the blower motor had three wires red, gray, and black. I have 12v at the red wire all the time but if I turn the fan speed up the blower doesn't turn on and I don't have any change in voltage at the gray wire or black wire. Assuming the black wire is ground with the gray being some kind of signal or reference wire shouldn't there be change in voltage at the gray wire when the fan speed is changed for off to low to high?
Submitted: 1 year ago.
Category: Cadillac
Expert:  Don 'Mo Lurch' replied 1 year ago.

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sorry for the delay............
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Greetings...... “Hi, I’m Don (aka MOLurch) and I look forward to helping you!”
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RED = 12 Volts +
GRAY = Logic from the Heater Programmer
BLACK = Ground -
Typically the Heater Programmer is the cause but the Blower Motor Speed Control at the Blower Motor should be replaced first

the Front Blower Motor Speed Control which is incorporated into the Front Blower Motor and is not serviced separately.
The Heater Programmer is located passenger side, behind das

Click Attachment below

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Expert:  Don 'Mo Lurch' replied 1 year ago.

I see you opened another "same question"....?
is there something you don't understand?

If I can help further, please respond