Wiring hazard

[Joe MacDonald]

This is a warning for anyone who drives an older or high mileage vehicle.

I drive a 2006 gmc envoy denali, approx 205 thousand miles.
On Wednesday on my way to work, I had an electrical fire under my dash. I managed to put it out but I wanted to make everyone aware of what I believe to be a hazard. After doing a quick web search I found at least 5 videos discussing how to change the blower motor resistor pack on the envoy/trailblazer series vehicles
Every video I checked showed a fan speed failure on one or more speeds, requiring the changeout of the resistor pack; this isn’t something new, resistor failure has been around for ever. But, in watching the videos, in every case i saw the connection point showed severe overheating and in most melting of the plastic.
I will be taking mine apart today and will post pictures.
My main point is this... from the time I smelled a faint burning electrics smell to open flames under the dash was less than 2 minutes. The cab was filled with smoke making it hard to see and breathe.I managed to get pulled over, vehicle turned off, found the flames and put them out, im not sure this could have been done on a busy highway. I was on a 2 lane 50mph road at 5 am with no other traffic , and i knew how to get to the blower assembly behind my glove box.
Joe

[k0wtz]

Joe I have had quite a few GM heater fans go out. Some of them are killers to get out.


never heard of a fire though. thanks for the info


bob

[Joe MacDonald]

Fan and resistor pack

[Joe MacDonald]

Wiring harness

[Barb and Alan]

We have a 2007 Silverado 2500HD. Last spring the heater fan quit and I found the resister to be burned, melted, and I am probably fortunate not to have had a fire. The dealer carries an updated version which (IMHO) should have been a recall but wasn’t. Obviously a poor design and/or execution. Glad you were able to extinguish the fire before it got serious.

[Green Frog]

Does anyone know whether this design feature is still present in the 2009 Trailblazer? My speed 4 on the fan doesn’t work, but the rest do...

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[Joe MacDonald]

The trailblazer would be pretty much the same, do you have digital or manual temperature controls?
Its an easy check, just remove the cover under the passenger side dash, and look up close to the firewall, you will see the fan and the resistor pack

You can find videos on YouTube
Joe

[Green Frog]

Thanks Joe. Mine is manual and it"s supposed to go to my mechanic in the next few days anyway, so I guess I'll just add that to the punch list.

Froggie