GMC Repair: Rear Climate Control, coolant levels, climate control

Question
2003 Yukon: the rear heating unit is only blowing cold air.  Could this be caused by low coolant levels?  All fuses are fine.

Answer
Hi
I would more likeley suspect the Mode door for the rear HVAC system.
If you could take it to a shop, You MAY find DTC's (Diagnostic trouble codes) for the REAR HVAC system. It sets certian codes for the door in question.
I have replaced a lot of them.... so I would more likely suspect this over the low coolant.
I hope this helps
Pawl