AC and heating problems

Laurence · May 22, 2018

Hello there. I hope that someone can answer this one.

I see there have been some postings about heating and AC problems. I have a 2006 GMC 2500HD with Duramax. It only has 138000 KM on it so far.

In the winter, the heater will start blowing ice cold air from both sides. I do the recalibrate sequence and it behaves for a while. I have driven many miles in -30 deg C weather with no heat.

In the summer, the driver's side will pump out the heat. The pass side is cold. The recalibrate only solves the problem for one restart. This heat issue has been around a lot longer than the cold issue.

Are these two problems related? What do I need to replace to fix this?

Thanks for your help!

Laurence

txab · May 22, 2018

Sounds like bad blend actuators

Formulabruce · May 23, 2018

This truck needs a new blend motor assembly ( tiny gearbox and motor) .

Laurence · June 16, 2018

Hello again. I replaced the blend actuator and I reset the system (recalibrate). It was wonderful to have AC again! But; the the same problem started again. Full heat from the driver's side. The pass side is cool.

The actuator I replaced is mounted under the duct work; accessible from underneath the dash.

Any opinions on what this could be?

Help!

Edited June 16, 2018 by Laurence

davester · June 16, 2018

There are two blend door actuators (so you can have separate passenger/driver temps). Which did you replace?

Laurence · June 18, 2018

Oh; there are two? I did not know that. Anyways, I replaced the one that is reached from the passenger side. Where is the other one? The motor I removed did not seem to have any defects.

Laurence

davester · June 18, 2018

It's near the dash brace going to the transmission hump on the drivers side. You need to remove the cover/shield running along the middle of the dash (along the underside of the dash). It's fun, several blind bolts that you need sockets just the right length to do them...

There needs to be two, so the two side can have different temperatures.

C/K Man · June 18, 2018

Driver's side actuator is on the bottom of the HVAC assembly, above the transmission hump accessible from under the dash. The passenger side actuator is on top of the HVAC assembly. It is accessible by removing the radio. Not too tough, you will see it in there a little to the right.