Is there a heater water control valve and how do I replace/check it? Where is it?
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1992 GMC Yukon Question: Heater blows cold air
Answer #1Bret Bodas from RepairPal Test Shop, February 20, 2009, 15:43Master
First of all, make sure the coolant level is OK, and the engine is reaching normal operating temperature.
Your vehicle has a temperature blend door, and it is activated by a little electric motor called an actuator. Check out autozone.com for instructions!