It's been a few days of hot summer weather here in NJ. Unfortunately I'm finding a glitch in my climate control temperature setting - it changes or "resets" to 24C with ignition cycles.

I always use farenheit (F) and typically set the temp to 68 degrees. Time and time again I get underway and begin to realize that the ac isn't that frosty. Palm to the head - oh yeah. I look down and she has changed to celcius 24 degrees. A quick adjustment and I'm back in business.

First I verified that the outside temp reading was accurate, yes she is.

Then I figured its low battery so I hooked up the charger to top her off. Sure enough she was taking between 5 and 10 amps for a while as she charged up to full charge.

Tonight was my 1st test drive to validate all ok. Turned her on and drove away, good news - temp was 68F no adjustment needed. But then I stopped at a store .

Bad news: when I restarted she was back to 24C. I set it to 68F. Then shut off the ignition, wondering to self if a battery lead was swinging open causing it to rest to a default 24C and I was losing memory each time I shut off ignition.

I turned on the ignition and watched carefully as the display changed from 68F to 24C ! Guess that kills the swinging open battery lead idea.

Outside temp is accurate, though of course it reads Celcius when this happens.

I will run the climate control test and see if any error codes are present tomorrow morning. In the meantime I wanted to ask and see if you may recall anything that could cause this?

I appreciate any thoughts or experiences that you might have on this.

Thanks,

John

 

One possibility. Have you checked/cleaned the In-car Aspirator? This is the location on my RHD 2005 XK8:





Panel has to be removed to access the assembly. There's a fan that draws air over a sensor to maintain cabin temperature:





These get full of dust and temperature settings go crazy.

Graham

 

I'd still be looking at the battery - what's the voltage across the terminals?

 

It sounds like your battery may be declining since charging it up saved your settings. If the battery is weak starting the car will pull the voltage down enough to loose stored settings. I just had this problem on my other car, a 2016 Ford Taurus. After starting the steering wheel tilt and telescope feature, mirror settings, pedal position settings would not go to the set positions sometimes. The battery sounded weak when cranking the engine and replacing the battery solved all the failures.