weird ticking from glove box area/hvac only blows hot air
 

So I have this ticking sound (sounds like turn signal) that randomly comes from my glove box area. Im sure someone else has had this problem. Any suggestions. Also I have the automatic climate control in my 1998 Blazer, the people that owned it before me said that they had a heater core put in the truck. No matter where i turn the temp hand, it always blows hot air out. Ive tried hitting the A/C button, but it just blinks a few times and then stays off. Every now and then the A/C light will stay on, but it still only blows hot air. I cant even get cool air from outside =( Summers coming up...lol Help!

There's a series of relays in the panel contained within the glove compartment. I'm not sure what the order is for vehicles with ATC, but it should be explained there. Chances are, that's where your ticking sound is coming from.
As for the AC... that's a bit more complicated. There are seven conditions, based on ambient temperature and system pressure, by which an AC system is diagnosed, with Condition One being normal operation. If you don't have a manifold gauge set and the know how to interpret what the pressure readings tell you, my recommendation would be to have a shop do a system performance test on your AC system, and you may want to consider a refrigerant purity test, as well. At this point, it could be anything... low refrigerant, excess refrigerant, bent fins on the condenser, blockage somewhere in the system, bad pressure switch... it's impossible to say what without a further diagnosis.
Also be aware that, if the repairs involve opening up your AC system to ambient air, you'll want to have your accumulator replaced, as well. The accumulator contains a desiccant which traps moisture and ensure that all refrigerant which travels onward to the compressor is in vapor form... this is a vital component in the AC system, and the desiccant will become fully saturated within minutes of being exposed to atmospheric air.

i know for a fact that your relay for the blinkers is behind the glove box. i had to change mine when i went to LED. yours could be going out and you might need a new one. the good thing is that they are only like 10-20 bucks.

as far as your a/c.
depending on where your position knob is, face, face and feet, feet, ect, the a/c will not work. same thing with the recirculation button. but the button all the way to left is the fresh air button. if you hit that and have the position knob on face, you should get air coming in when you are driving with the fan off. all depending on speed, it will be more or less. the other problem that you might have is that the blend door is stuck. that takes a bit more to fix. it is controlled by a motor, not vacuum. you can remove it if you have the right tools, but its complicated.

here is another thread with a similar problem, except they didnt have heat. you have heat, no cold air. but you might be able to learn something.

Ok so i have found the blinker relay and that problem is solved. as far as the constant heat, yesterday i attempted to pull out the actuator and failed miserably, however when i was down there i pulled the vacuum lines off (orange and grey) that apparently went to the blend doors. nothing happend. they didnt even have vacuum running to them which makes me think this could be a vacuum issue under the hood. i popped the hood and if facing the engine, i found a vacuum hose that runs from the driver side from a "t" fitting that dropped down behind the motor....the line was hard and broke and not hooked up to anything. not sure if this could be my problem or not, but i cant seem to trace it =( any suggestions?

I am having the same problem with a clicking sound in the glove box area. Where exactly did you find the relay? I am new to these vehicles and any help is appreciated.

If you open the glove box (make sure you empty it) in the upper left corner you will see a little hook. kinda push up on the hook and drop the glove box open. look down to your right tward the floorboard and there will be a longer relay box there. it should be the only one =D Hope this helped. :icon_viking:

the blend door for the hot and cold is not controlled by vacuum on your truck. its controlled by an electric motor. check out this thread

ok..so after a lot of cursing, a few busted knuckles, a little more cursing, i have finally got the actuator out!!! (does a little dance) after removing the top, the biggest gear is broke in 2 diffrent places. looks like a new actuator for me, however i was kinda curious if the gears should turn freely when you move them. if so, i was contemplating trying to epoxy the cracks...any suggestions?

That does help, thank you very much.:icon_toast:

I think if you lift the little motor out, you should be able to turn the gears. Might also try to see if the motor will rotate by fingers or reconnect the elecrical connector and hold the actuator in your hand; turn ignition key to ON and then move the HVAC temp control between full hot and full cold to see if everything moves. Be sure to have the temp door in the correct position as the actuator when re-installing it.

I have read that finding the correct actuator can be a problem. There appears to be a slight difference with the aftermarket one so that it will not fit correctly.