Hello guys,

I have a '98 4 Door 4WD Chevy Blazer.
One of its (many ) problems is that the HVAC blows cold air no matter which setting is chosen or how cold it is. (By the way it's around 0°C here, so getting really cold in there)

Have read there is a problem with the blend door actuator mostly.
So for diagnostics and maybe a quick fix I followed an instruction from this forum to find and maybe demount the actuator.
The instruction says it would be behind the glove box.

But there are only two actuators behind my glove box, one to regulate the air circulation and the other one to regulate the air flow direction (you know head, feet, defrost). Both are working perfectly.
There is also a mounting for an additional one but there is actually no actuator, also there is no vacuum-hose and as I could see no unconnected parts there.

Is there an alternative place where the blend door actuator could be mounted?

Before someone mentions - there is nearly no chance the radiator is jammed.
Yes, I use the original Dexcool, but I got the cooling system flushed and refilled a month ago.

Thanks and greets from good ol' Germany

 

With the engine at normal operating temperature, first make sure both heater hoses are nearly equal temperature where they enter and exit the firewall. They should both be hot to the touch with bare hands.

The blend door actuator is all electronic, (no vacuum lines) and it has one electrical connector. It is mounted on top of the heater case. Bare minimum, the glove box must be removed to access it. There are three screws that hold it to the heater case. This one is for manual HVAC, not automatic climate control: Dorman Products - 604-100 The actuator is used to regulate outlet air temperature in the cabin.

 

So as Xmas and New Year are gone, I had time to check the temperatures.
Both hoses are equally hot, but both are only lukewarm (outdoor temperature was 23°F so rather less than lukewarm).

I reckon this means my radiator is clogged.
Just wondering why the engine doesn't overheat.

I have noticed that the HVAC-control (automatic climate control) gets really hot at the upper site, is there any chance this is related to the problem?

What would be the next steps?
Another flushing of the cooling system, replacing the radiator or maybe replacing the HVAC-control?

 

Is the engine running @ 195 degrees? Sorry if I didn't see that previously mentioned...Jerry

 

Both hoses should be hot to the touch with bare hands. Depending how tough you are... maybe 2 to 4 seconds is all you can stand. If you have an infra red thermometer, the lines should be ~180 degrees F.

I see you are in Germany, is this vehicle RHD, (right hand drive)?

 

The engine is running around 195°F (maybe 1° more or less).

I don't have an infrared thermometer here, but even without one I can say these are not nearly 180°F, I would assume something between 86 and 104°F - as I said my hands were really cold and I could hardly feel they are warm.

It's an original US import so it's a left hand drive.
By the way in Germany we are driving on the right, too

 

I figured being in Europe I'd ask. Just curious which drive you had

If it's running at 195F at the ECT sensor on a scan tool, that's just about perfect. If you're only at 90F at both hoses, and no heat from the heater, chances are the core is plugged almost solid. If coolant can't get through, the hoses will not get hot. To test the theory, you could connect the two heater hoses together and bypass the heater core. If the hose gets hot, the core is plugged up.

 

Had a similar experience with my 96. With Captain Hooks help solved the problem. It appears I had a stuck thermostat. It was stuck open and never got much over 120 degrees. Both hoses seemed the same temp but luke warm. I removed the heater hoses at the the motor put a coupler (Used a back flush kit was like $8.00) it is a tee with a hose connection on the branch and two male ends to go into the heater hose and the 4' hose. I made it 4' on both so I could flush it the other way. On the smaller hose did the same only left that hose in a large pan. I hooked up the garden hose to the hose connection of the back flush kit and cleaned out the heater core. It started to run slow at first and after about 3 gallons it ran clear. I then reversed it and did it again. It helped a lot. I did the large hose 3/4" first and then the 5/8" the kit came with both sizes.