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Matt, Engineer
Category: Buick
Satisfied Customers: 21610
Experience:  Honors degree in Mechanical Engineering, worked 8 years as a Formula 1 engine engineer.
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Have an 04 Buick Rendevous the heater blows warm air on the

Customer Question

Have an 04 Buick Rendevous the heater blows warm air on the floor setting but only cold out the defrost. Checked the fuses and there fine we even had it flushed and bled out with no cure. Someone told me to unhook the positive battery post for 30 seconds and that might do it. what do you think
Submitted: 1 year ago.
Category: Buick
Expert:  Matt replied 1 year ago.


I'd say that the blend door flap for the defrost air is stuck or the motor to move it is faulty

This flap is controlled by the temperature knob / dial etc and I think is controlled with a small motor for your car so the thing to do is first get access to the back of the control knob and measure the voltages is present there, then trace the wiring back into the dash from the control to locate the motor.

It’s worth first checking the fuses for the fan / control circuit

I'd recommend first removing the glovebox ( undo lower edge hinges from dash) to gain access to the dashboard inner and also allow you to shine a torch to the back of the central console so you can start tracing the wire back and see how things are put together

Expert:  Matt replied 1 year ago.


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