Trailblazer heating problem!

diamond725
Posts: 2
Joined: Thu Mar 21, 2013 6:54 pm

Trailblazer heating problem!

Unread post by diamond725 » Thu Mar 21, 2013 7:29 pm

I have an 03 Trailblazer EXT 6cyl. 4.2... There's no heat coming from my front , middle roof , and rear vents. Only from the defrost vent , and barely lower dash vent. Great truck , bit im freezing my butt off . Can you please help bring some warmth into my life? :roll:

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ProTech
Posts: 651
Joined: Wed Oct 17, 2012 10:08 am

Re: Trailblazer heating problem!

Unread post by ProTech » Thu Mar 21, 2013 11:18 pm

If the truck is producing enough heat when it comes out of the defrost position, then you can assume that the problem is not an issue with the heater core or coolant system. More than likely you have a mode problem, where the mode door is not functioning correctly to route the air to the vents you desire. This can be anything from a bad control head, to a faulty mode door actuator, or a broken mode door, or a wiring problem.

Usually an issue like this will require service from a qualified technician. Also, if there are problems as mentioned above, it will more often than not set a trouble code in the HVAC system. This code can be retrieved from a technician and will aid in diagnosing the vehicle.
More information and Mode Actuator Picture.

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