To make a long story short, my car was at the dealer to get the driver side lower seat cover replaced under warranty due to factory defects.
I dropped the car off with working heated seats; after driving home I noticed the seats now no longer work. Some Notes:
- The dealer disconnected the battery (see below related HVAC module question)
- All Primary plugs (at least the ones I can see under the seat with out removing it) appear to be plugged in.
- Both the Relay Trigger Fuse & Main Heated Seat supply fuses are good & pass voltage when they should.
- Both of the heated seat buttons light up and stay on when pressed
- Each seat has its own ground (doubt its a bad or loose ground)
- The relay control box is under the driver side seat, I have not removed the seat to test it yet. According to the wiring diagram each seat has its own relay within the box, I also find it hard to believe that both could be bad at once unless this box has some kind of common circuit for both seats (doesn't appear to).
The question: Reviewing the wiring diagram; apparently the HVAC Control Module logic is what triggers the coils in the heated seat relay control module to gate power to the heating pads in the seats. Does anyone on here know if the HVAC control module needs to complete some sort of re-learning cycle or drive cycle when the battery is disconnected? Is this module even that smart?
As I see it now the only possibilities for both seats not working are:
1. HVAC Control Module needs to be re-learned or configured after battery has been disconnected?
2. Something is not plugged in; although I don't see anything unplugged under the driver seat (with out removing it and looking further) that would affect both seats. The main junction plugs appear to be connected.
3. Bad Relay Control Module
Wiring Diagram: Ford Service Manuals - Wiring Diagrams
Any input in regards to how the HVAC Control module logic operates the heaters
(or anything ive missed in general) is appreciated.