Even the most venerable vehicles can have some minor flaws when they are engineered and designed. One such system turns out to be the blower motor speed controller for millions of GM trucks and SUV’s. This particular problem only applies to vehicles with automatic temperature control systems.
This information applies to the following vehicles:
2003-2006 Silverado/Sierra, 2003-2008 Chevrolet Trailblazer, Buick Rainier, GMC Envoy, 2003-2006 Escalade, Tahoe, Yukon, Suburban, Avalanche
Initial failure symptoms usually consist of one or more of the following issues:
- Blower Motor Stays Running Even When Truck Is Off
- Blower Motor Doesn’t Work Consistently, (Will turn on randomly)
- Blower Motor Runs at Wrong Fan Speed
- Blower Motor Doesn’t work at all
If you have the automatic temperature control and exhibit any of the above symptoms, suspect the blower module to be the issue. The original design had a small three-pin connector which, as it turns out, is not sufficient to draw the amount of electrical current that flows through the module and into the blower motor. One cause of failure was from these pins heating up repeatedly and eventually causing stress to the module which would create a failure.
Old Style, Problem Prone Blower Module
This part has been completely redesigned, which now includes a heavier duty connector. It is easy to install and just requires cutting off the old three-pin connector and splicing together three wires. We suggest soldering these wires together to create a permanent good connection, but butt-crimp connectors can also be used. The newly designed module and connector can be seen below.
New Design Blower Resistor / Control Module
We have the part available here. (Please verify that your vehicle is listed on the compatibility chart.) It is a very economical repair for a very frustrating and inconvenient problem.
One important note: manual temperature control vehicles use a completely different part. They use a blower resistor which actually has 7-pins and has entirely different symptoms.