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Ask Gm Tech (Cam) Your Own Question
Gm Tech (Cam)
Gm Tech (Cam), Cadillac Mechanic
Category: Cadillac
Satisfied Customers: 29428
Experience:  GM Grand Master Technician 2007. 14 years experience.
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I have a 1999 Cadillac sts had to change battery now heater

Customer Question

I have a 1999 Cadillac sts had to change battery now heater does not work properly. It will only stay in vent mode and blows cold air out of one and hot out of the other
Submitted: 1 year ago.
Category: Cadillac
Expert:  Gm Tech (Cam) replied 1 year ago.

HI there, I am Cam. This is likely just due to normal wear that the computer has learned, then forget when you changed the battery. Here is what you can do to relearn that. Usually all that is required is the system needs to be re-calibrated 3 times to clean the feedback circuit in the actuators off. This is done by removing the battery cables for 10 seconds. Attach the battery then start the engine for 3 mins. Shut the engine off and then repeat this 2 more times. By removing the power, you force it to recalibrate which involves a full sweep on that feedback circuit. This can clean if off and most of the time it corrects it. IF not then we may need to replace the actuators.

Customer: replied 1 year ago.
far that didn't work, it doesn't make sense just replaced battery
Expert:  Gm Tech (Cam) replied 1 year ago.

I understand your frustration. IT does in a way though. The system uses a feedback circuit inside that actuator. The module monitors the system and adapts over time to the small changes. When it was reset, it forced it to try and relearn quickly what it took a long time to learn and now the amount it has to learn is outside of what the programming allows.

With this not working properly after that, I am sorry to say we need to replace the actuators that are not working. Which side is not responding properly to the temperature changes?