Having problems with your 2004 GMC Sierra 1500 Crew Cab ?

Bad odor (Wire sheathing?) from vents when fan is on. We definitely have an intermittant (3 or 4 times in past year) driver side actuator problem. Cannot tell if odor is coming from all vents or not. Nothing obvious under the hood and all gages remain unchanged after 10 minutes or so driving. We think maybe it only happens when the heater is on. Any ideas? Thank you Ryan

Posted / edited by AnonymousUser on : 14-10-2019

Answers :

The heater core is bad it could be leaking and thats what the smell is coming from. you only smell it when the heat is on is because air flows throught the heater core to warm it by the hot anti freeze that flows through the heater core see if you anti freeze resivoir is low.
Ive run into this problem many times, what is happening is theres leafs and other debri in the heater box, there a blower resistor that controls speed of blower, this unit has open resistor wire coils that heat up to desapate the heat and what happens is the debri is lighting up and bruning, dangerous fire hazard. remove blower motor and resistor use vacuum to clean out,you will see resistor area with debri, the resistor is screwed into box near the blowermotor, hope this helps,
Repair Help & Product Troubleshooting for 2004 GMC Sierra 1500 Crew Cab

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