I recently purchased a 2004 Tahoe and my rear ac blower only comes on when it wants. It never comes on when I first turn it on. It doesn't matter if I have the controls set to the front controls or back. If I leave the **** turned on, it will eventually kick on, but it is never a set amount of time or a specific circumstance that triggers it on. After it finally comes on, if I turn it off and try to turn it back on, sometimes it will come back on but sometimes it never does. Does anyone have any suggestions? Also, it blows cold air only when the front ac is on, otherwise it blows warm air. Is this normal? Thanks for any input.

 

Best guess is either a switch or control module problem.