I have a 2012 Ford Fusion. Recently the cabin temperature control started acting up. I would turn on the A/C and sometimes the A/C would seem to stop and the heat would come on. Now even with the temp control turned to coldest and the A/C off, the heat will randomly come on. Temperature outside here is still in the 70s. The problem is random. The system might work fine for 3 days, then act up twice in one day. Naturally it rarely acts up at the repair shop.
Our repair shop replaced the electronic controller in the dashboard and the plug-in harness for the controller. That didn’t work. The dealer had it for 3 days and couldn’t find anything wrong.
I am looking for suggestions on how to troubleshoot the problem. Multiple trips to the repair shop and replacing all the obvious parts haven’t helped. Any suggestions? Are there people who specialize in working on climate control systems in cars?
We are just about ready to just get a new to us car, but those things are expensive!
Sounds like a Blend Door problem. Either mechanical or electronic.
Do you hear any funny sounds? Clicking or thumping sounds?
Another possibility is the A/C clutch is not engaging, which should be a quick diagnosis which the shop should have done, but hey shops…
I thought of the blend door. But I don’t hear anything unusual. It is worth investigating further.
A major problem is that this is an intermittent problem. In can give us trouble for days and literally go away while we are driving to the shop.
I checked the clutch the first time I was at home when it failed. The clutch was engaged. As you say, the shop should have checked it and I am sure they did. The one clue was when the problem appeared for the shop their instruments showed the heat on when the A/C was switched on. That is when they replaced the controller. It worked for a couple of weeks after that. The subsequent failure convinced me that it must be the connectors. Eventually the shop replaced the harness for the controller and the dashboard environmental knobs. Didn’t solve it either.
It spent 3 days at the dealer but never acted up.
I would almost bet that something is interfering with the thermostats ability to sense the cabin temp. Not sure where your thermostat is located but it may have a piece of trash covering it.
When I first saw the topic title, I thought, “Ooooh, cold fusion!!” Then I thought, “no, wait…”
thanks. I will look into that.