Front heater works perfectly but rear heater is just blowing cold

The heat in that vehicle is controlled by a blend door that regulates heated air flow. It is operated by an electric motor/actuator. The problem can be that the actuator is stripped or inoperative or the door itself could be damaged. This is what needs to be determined by examining the actuator and see if it is responding to heat change commands or not.

Try pulling fuse in picture for sixty seconds with key on, then reinstall. It may reset actuator in other picture otherwise that may be the problem and not opening door so it will heat.

Hi,

If the fan is staying on high all the time regardless of speed selection, chances are the control module itself is bad. Since the lights don't turn on any longer, that is my first suspect.

If you take a look at the attachments below, they provide the diagnostic for an auxiliary blower motor that always runs. See if you feel comfortable performing the procedure.

Here is a link you may find helpful:

https://www.2carpros.com/articles/how-to-check-wiring

Let me know what you find or if you have other questions.

Take care,

Joe

See pics attached.