Can you get a picture of what you are seeing on control panel? The only reason, this sounds like a control module issue that it is not responding to the buttons you are pressing.
However, this system includes what is called a FET. This is a transistor that the control module uses to alter the blower speed. Basically it is a way of changing current flow so it uses this do that.
This means that the FET could be shorted but it is more likely to be a control module issue. The reason is, if you look at the wiring diagram below you will see that the blower motor is supplied voltage through a relay. This means the control module provides the ground for the system.
It also provides the ground for the two relays prior to the blower motor relay which means the control module is most likely causing the blower motor to stay on.
The way we need to test this is is to check the voltage on the FET circuits and then the ground circuits as well for each relay.
https://www.2carpros.com/articles/how-to-check-wiring
Please run through this diagram and let us know if you have questions on this.
Basically if you just want to get the voltage on each of these circuits and we can determine what is happening with it based on this. We just need to know if the system was off when you took the measurements.
Please let us know if you have questions. Thanks
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Jul 31, 2021 at 4:00 PM
