Hello everyone!

I know I am new, and I am just starting to reach my breaking point with this truck, it has so many quirks that it's just getting to be a bother, so rather than guessing, trying to search (Which this site has already been helpful for other projects or testing) I figure I could just introduce myself, and my world of problems with my 98 Bravada.

First off I bought this not too long ago as my other car is down for surgery as it is getting an engine transplant, and I wanted something that had more capabilities, especially in winter in Illinois.

When I bought it, the wipers didn't work, was covered in dog fur, was missing trim pieces, and other things.

Currently I have a lot of issues resolved, but I still have the following:

My computer climate control is a mess, and I am beginning to think it's the actual HVAC system, not the components such as a blend door actuator.

Sometimes, I will turn the temperature to heat, and I'll get heat for a second, then it goes back to cold, and I hear the actuator making a ton of noise, sometimes it pulsates, sometimes it just goes all over the place, then eventually, it gets its act together and gives me full heat.

The blend door actuator doesn't operate in the middle temperatures, it's either full hot or full cold. If I turn it off heat, it reverts to full cold. I took apart the actuator to inspect for a cracked gear, it's all fine, and to be safe I did add glue to it for reinforcement. I even left it off the blend door, and operated it, and was able to see it operate fine, just it decided against working. I tried switching vent to floor, to defrost, nothing.

I did pull the RDO/BATT fuse, and sometimes that makes things worse, and the blend door does nothing. And eventually it comes to life and will operate as described above.

But sometimes, it just refuses to give heat, and I have to go back and forth multiple times with the temperature **** to get it to lock into full heat.

I can see how it could be the actuator as it has the sensor to determine where the position is. But could also be the computer, or even temperature sensors around the car, I found 2, apparently there are 3. I also notice it never truly shuts off either, it always has some fan movement, not sure if that's supposed to work that way or not.

Second big issue:

As I am driving, there is a grinding noise that always seems constant. As I use my brakes it is present, even checked the brakes but seems alright, I can't pinpoint it, but it seems to be coming from under the car.

The car does drive fine except harsh shifting between 1st to 2nd gear if I give her moderate acceleration, but if I let off, it shifts smoothly, I am hoping a fluid change will fix that. It has about 129k miles on it presently.

Now the parking brake doesn't work, I am wondering if it is related or not, but I have yet to take the rear tires off and inspect the parking shoes.

Other than that, this truck starts like a brand new vehicle, it doesn't hesitate at all, the engine feels great, transmission feels great, not sure how AWD is since it's computerized, no error lights when I drive, and no codes when I scanned before I bought it.


Seeing as this is the first GMT330 I've owned, I figure maybe others have already experienced my headaches and can help out a bit.

 

Your HVAC issues sound exactly the same as mine. I haven't been able to figure it out yet. My actuator motor works fine and there are no codes for it in the system. As far as grinding while driving, it sounds to me like a wheel bearing.

 

There is a vacuum hose that goes from the back of the engine, over the brake booster, and to the driver side fender that can rot out that helps control the blend doors. I had similar issues and after replacing this hose it fixed much of my problems.