The most common problem found when the blower motor wont shut off is a sticking relay. The blower motor relay is located in the engine compartment integrated power module(relay box) at the front left of engine compartment.
Start the vehicle and turn the blower on. Turn vehicle off, and if blower motor is still running, try tapping hard on top of the relay. If blower motor cuts off, then replace the relay.
You can also swap out the blower relay with the rear window defogger relay. Now, start engine and turn on blower. Turn off engine and remove key, if blower motor is off, then you know relay is bad. Replace relay.
I tried both tapping and swapping the relays that does not fix the problem. The blower is running at high speed even when the heating system is turned off. It is very cold here
Sorry, lost my online connection last night due to snow- do you still need assistance?
Still need assistance.
Tried your suggestions.... tapped on the relays and swapped relays. It did not correct it.
Fan continues to run constantly (as soon as the key is turned in the ignition) at the highest speed even when the heat/ac power button is turned off.
Please understand it is very cold here. Could that be causing a bad connection?
No, the weather should not affect the connections.
Ok, there is one more relay to check, the run relay- it is in same relay box:
Try the same tests as before. If relay is good, then problem will either lie in the Body Control Module, the Climate Control Unit itself, or possibly the front blower power module., and will require a factory level scan tool to test them.
Unfortunately, yes, at least for the diagnostic troubleshooting. Once they determine the problem, you can decide whether to have them repair, or do the repair yourself and save on labor.