In the summer when my AC in on and running for a while, It suddenly will go into heat mode on the drivers side only. This was random throughout last summer.
Now enter winter. My heat will come on only at 90 degrees. If I lower to 80 it will go cold, drivers side only. It also take forever to warm up. I have just dealt with it for a while. Now I have to take a trip to Idaho from So Cal and I want my heating system working properly. It does not get that cold here in So Cal but my engine temps will barely go above the first quarter line. When I bought it new in 04 it always ran at 185 all seasons. Anyone got any ideas?

Might try A/C system actuator calibration first. With key on, turn off A/C system and all other electrical such as radio, etc. Shut down engine. Remove negative battery cables for 2 minutes. Reattach cables and start engine. DO NOT TOUCH the A/C controls until two minutes have expired. During this time the A/C system is going thru a self calibration of the actuators. After the 2 minute time period, try the controls and see if problem has gone away or changed somewhat. I have had to do this several times on some vehicles to correct problem. If problem remains, the left blend door actuator will need to be replaced. Access is to the left of center of dash in area above accelerator pedal area. Radio settings may be lost during battery shutdown. Pulling the HVAC fuse will accomplish the same thing, but finding the fuse can be more problems for some.

Thanks, I know where the fuse is.

Moved to Interior