Low A/C warning while using heater.

[Spazzaroth]

Now that the weather is cooling off down here in South La I've started getting a crt warning for low A/c coolant whenever the heater is running.  I know the coolant isn't actually low because I spent a weekend setting it just right this summer and the pressure hasn't changed.   Has anyone had this problem?  It seems to only cause an issue when the compressor isn't running.

[Ronnie]

3 hours ago, Spazzaroth said:

I know the coolant isn't actually low because I spent a weekend setting it just right this summer and the pressure hasn't changed. 

 

I wouldn't assume the pressure is good now just because it was in the summer. As ambient temperature goes down so does freon pressure in the system.  Only way to know for sure is check the pressure.   It could be the low pressure switch but I'd bet on the Freon being low. 

[padgett]

"compressor isn't running. " - are you sure ? I've never seen the "low" warning appear when the compressor is not running (in econ).

[Spazzaroth]

Ok well I checked the freon.  I had stopped getting the low coolant warning a while ago. But my AC isn't blowing cold anymore. And it looks like my coolant is now over charged even though I haven't done anything.  I'm very confused.

[Cargirl]

Sounds like the low pressure switch may be bad. Its pretty easy to replace and you need not purge the system to change it. Check Reatta owners Journal for location.