Reading through the workshop manual. It states that after replacing the ATC module, you need to reset it. If so has anyone done this & what is the process?. This is a 2006 4.4 V8 petrol running the high line system.

Also can someone confirm, that when you dial in a lower temperature on the drivers side to that of the passengers side, the fan speed increases. However doing the opposite, the fan speed does Not increase & remains the same (All ready replaced both heater temperature sensors).

I've changed my ATC module a while ago & still trying to resolve the heating issue. AC works lovely. Just the heater, although it will work. As soon as you drive at a constant speed it blows cold. Reduce the speed to say around 30 mph or less & you have heat again.
Using the auto function will work, but the temperature settings seem out to the ambient temperature ( Outside temperature reading is correct).
My thought is that it may need to be calibrated, although reading everywhere on the Net, there is no mention of a reset being required.
Thought I would ask the question prior to obtaining another ATC module.

Bump:- Can anyone just confirm if altering either temperature dial increases the fan speed on both sides, this would at least give me something to go on. Thanks.

My AC doesn't work because the compressor is shot but changing the dial position does not change the fan speed. Don't know if that helps but there it is.

Thanks for the reply, may only work on one side then.
I need to change the ATC Module & see if that cures it. As put the heater on yesterday, whilst driving at about 60 mph & no heat. Fan speed increased, all dials set to Max - Nothing