I have a 95 blazer LT, 4.3 auto, 3 button 4wd, with manual climate control. Last night after using the heat for a few minutes it will now blow nothing but hot air. I have searched the forum, checked my vacuum lines under the hood and behind the climate control..all fine. I went to the salvage yard and got a new climate control but that didn't fix it. in reviewing the forums, I think its the heater blend door. Does this sound right? How do I get to the door? I should mention that it started blowing out the defrost on acceleration which I know is vacuum lines in the dash.

I am thinking that its thevacuum line to the blend door. if anyone can correct me if I'm wrong and direct me to it, I would appreciate it.

 

I don't know the '95 blazer. My suggestion is look at the heater hoses coming out of the firewall and look for a valve inline in one of 'em. (it would have a single plastic vacuum line running to it) If you have one and if the valve froze or the rubber diaphragm in the pot went bad that could do it.

 

Coolant is always flowing through the heater core. Your problem lies inside the HVAC housing, specifically with the temperature door. It is possible that the actuator has failed. I'll have to look up the system schematic for the 95 as I know it is not the same as the 98+, but I also do not think it is the same as the 94...

 

Thanks swartllk....I went out and took another look at my setup. I turned the key to the on position and then adjusted the temperature and could hear the actuator motor working, albeit slowly. I then tried it and was able to get cold air. Adjusting it while the truck was running would get me heat, but I was unable to go back to cold air. After playing around with it, I found that if I turned the climate control off OR vent and low fan, I was able to get the temperature to adjust. This tells me that the actuator motor is on its last legs. While this is not the ideal situation, it is a passable workaround for a week or two until I can get into the dash to work on it.

Also, more kudos and thanks to swartllk....

https://blazerforum.com/forum/showthread.php?t=29981

The how to guide on actuator motor replacement. Doesn't seem all that massive of a project, at least at this point

Anyway, thanks for the information. I'll go check out that blazer at the yard first since it has most of the dash removed which will let me see how everything is attached.

Thanks again!

 

I still have not had the time to look up the layout of the early 2nd gen HVAC systems so I am not sure if that will apply to your truck. I think that it does, but...