Hello All:

My '12 Fusion SE 2.5 Auto HVAC system (manual climate control) has been degrading over time. At first the air would go randomly hot, and if I restarted the car everything would go back to cold. Then, it slowly got warmer over time. Then the AC didn't work at all, and the compressor is not engaging. I could adjust from ambient air to hot, and now just ambient air regardless of what the temp selector is set to, AND the panel is the only zone that works (however this could be because I was experimenting with Forscan)

My standard scan tool doesn't show hvac codes, so I ordered the OBD Link cable and downloaded Forscan. Last night I picked up the following codes from Forscan (look at the HVAC codes - I believe the first one is due to disconnecting the battery).

In addition, my ambient air temp was reading 37 C, which it was only 66 degrees F last night. My evap temp sensor is reading -37 C, which obviously isn't correct. However - before I automatically assume it's an evap temp sensor and start tearing into the dash, I want to address the fact that nearly EVERY component is triggering a code. Forscan also told me that there was no fault with the ac clutch, and that the computer was showing that the AC was off when the control panel had it turned on. I'm wondering if the control panel is shorted and causing problems with everything.

Can anyone shed light on where I can look next? It's hot out there!! Any help is greatly appreciated.

 

OK here is the description for each code from Ford, not sure if you care about the GEM fault codes or not. Due to the numerous short/open fault codes I would suspect harness damage. You could remove the HVAC module and inspect the wiring harness for visual damage along with inspecting the wiring near the GEM, if you remove the glove box you will be able to see more of the wiring harness.
HVAC
U0423-68
Invalid Data Received From Instrument Panel Cluster Control Module
B1B71-15
Evaporator Temperature Sensor: Circuit Short to Battery or Open
B11E7-15
Air Distribution Damper Position Sensor: Circuit Short to Battery or Open
B11E5-15
Left HVAC Damper Position Sensor: Circuit Short to Battery or Open
B1086-13
Air Distribution Damper Motor: Circuit Open
B1083-13
Recirculation Damper Motor: Circuit Open
B1081-13
Left Temperature Damper Motor: Circuit Open

GEM
B106E-60
Solid State Driver Disabled Due to Short Circuit
B2A33-60
LED Backlighting Output Circuit Short To Ground
B2A3A-60
Puddle Lamp Output Circuit Short To Ground

 

Hey Scott,

Thanks for your response. As it turns out, the HVAC harness WAS damaged - it wasn't clipped into place and therefore wasn't completely engaging all the pins (I suspect the Ford dealer who recently did an airbag recall).

I was able to repair the harness by straightening the pins and making sure it was fully engaged and clipped in properly. After that, I cleared the codes and reset - NONE returned.

That said, the A/C clutch was still not engaging. I inspected the harness for damage, checked all fuses and relays - everything was good. I jumped relay #43 and found that the the clutch WOULD engage if forced, so it was good and the wiring was good, but the PCM was not calling for engagement. The only answer I could come up with is low coolant pressure. I put a small amount of R134a with dye into the system and quickly found the leak with a black light and glasses. A valve cover bolt and high pressure line had been rubbing against each other and wore a hole in the high pressure line - therefore building pressure was impossible. Check your aluminum high pressure lines and make sure that nobody has leaned on them over the years - if so they might be in contact with something they shouldn't be in contact with!

Called TEN Ford dealers - NO STOCK. Motorcraft parts are on indefinite backorder because COVID.

Murray brand aftermarket IS available through Oreilly's.

Replaced the lines with new o-rings. That was an easy job. Then rented a vacuum pump and manifold gauge set from Oreilly's. Evacuated the remaining moisture and air from the system, recharged with #46 Pag Oil (important to use #46), and 22 oz of refrigerant as called for by Ford. It's as cold as a meat locker in that car now.

If anyone needs help with any of these steps, reach out. It was a longer process than written above, but those are the major steps. It's NOT always the evap temp sensor!!

Z