Hey I'm kinda new to this fourm first post
I've read a lot of good things on here that helped me but one problem I can't seem to get help for...this is my second blazer/jimmy first one was a 93 4door blazer.. I picked up my 94 2door jimmy 275k miles runs like a champ now after a full tune up. And I just completed my first ever heater core change (I've usaly bypased them) took about 5 long hard agervating hours... Well when I first bought this jimmy I noticed the temp guage did not work as it should and heater core was bypased from leaking ( I assumed because the antifreze stain and when I pulled it out some how it looked bent up out of shape)
But after installing the new on I turned the heat on waited to warm up about 10 to 15 mins and it blows warm air not hot like it should be but I'm thinking that maybe the temp guage has something to do with it? The temp guage when I turn the key on kinda just moves up a tiny hair and then bottoms out. So if some one can help fix this problem that would be great!! Thanks!

 

I've read how to test the sensor on the pasanger side grounded it out and and the guage peged but I don't know if that is good or not? Can some one shed a lil light on this please!!
Thanks

 

as far it not blowing out "hot" air goes, it doesn't have anything to do with the temp gauge, you probably need a new temp sensor, and considering how many miles is on the motor its more then likely needs replaced, I replaced the one on my 93 blazer and its been working right ever since.

Now for the warm air situation. have you changed the thermostat? its probably stuck open and now allowing your engine to warm up properly, but even still, if you drive it long enough down a highway it should eventually get "hot".

Just my 2 cents.

EDIT: by the way, your motor has 2 sensors on each side for the water temp, the one on the driver side sends signal to the blazer's computer, and the one on the passenger side is for the actual gauge on the dash. check the wires and they also have a big problem with the plug going bad on them so if you ever go to a junk yard its good to take a couple of the sensor plugs and just splice the wires and put a new plug on I think the plug itself was actually what was wrong with mine.

 

Thanks for the reply
Is there a way to trobleshoot the plugs
Oh and my coper pipes onthe heater core are getting warm and eventaly gets a lil warm on the inside just take a lil time

 

Make sure your vaccum lines going to your Air select door (The door in the vent system that chooses inside air or outside air) is working right. You cant heat all the air if only half of the air is coming in from the outside, which is where a heater on most settings except for a/c gets its air from is the outside.

 

Here is a update found out what the deal was it was the thermostat. After what I had to deal with at nappa and what the thought I needed and what I realy needed I got the right part. Switched it temp gauge works and heater gets hot as hell temp runs at 210 constant and I flushed the rad again. Well thanks