No Heat

Well here is the problem, I can't get any heat to come out of the vents, it only blows really cold air no matter what setting I have it on. I thought i might of had a plugged heater core, well i took it to the shop today to get it looked at and they said there is nothing wrong with the heater core. The guy looking at the car told me it was an electrical problem with the Heater/Vent Module. I was just wondering if anyone out there has any idea what it will cost to get this fixed or any suggestions for a quick fix.

Well here is the problem, I can't get any heat to come out of the vents, it only blows really cold air no matter what setting I have it on. I thought i might of had a plugged heater core, well i took it to the shop today to get it looked at and they said there is nothing wrong with the heater core. The guy looking at the car told me it was an electrical problem with the Heater/Vent Module. I was just wondering if anyone out there has any idea what it will cost to get this fixed or any suggestions for a quick fix.
yes i have a 2000 s-10 blazer that is giving the same problem.
i thought maybe it was a climate control issue. like it is still warm weather in tennessee. but if you get to the bottom of this let me know.
thanks
Tracy

Did you look for a vacuum leak at the vacuum ball on drivers side fender i believe?

Did you look for a vacuum leak at the vacuum ball on drivers side fender i believe?
no i have not , but i will 1st thing in the morning.
i forgot all about this problem until i read your post .
well i still have a extended warr. so if it is somthing small i will fix it.
but other than that it is gm problem.how about you. find any problems with yours. what kind of blazer do ya have.well mine is 2000 s-10 bzer
i have some performance parts installed,like a cold air intake sytem
this was money well spent.a hpertech chip,flow master 40 series mufflers
with high output cat. converter,under drive pulleys .it is sitting on corvette rallys 245 60 15 tires white letters out flat centers and rings.lowerd 2 1/2 in rear , zq8 suspension,i am thinking about a cowl hood but dont know how long i will keep it.i sold a cowl about 2 years ago and practly gave it away.should have my asssssssssssssssssss kicked on that one .
good luck

There have been alot of threads lately about it look into it .

you have a warranty, get them to fix it.

you have a warranty, get them to fix it.

Just wondering - did you get it resolved yet? I'm having the same problem on my '98...

I am having the same problem on my 2000, and for a while could hear what I thought was a vaccuum leak coming from the heater controls. Now the leak has stopped, but there is no heat, and it seems as though it has a mind of its own as to where the air blows out

make sure you have the correct levels inside the radiator. 2003 winter
was really cold and I found that the dextron needed to be replaced.
Some people think that you can leave the fluid in there for 5 years.
Well your making a mistake. GM says Five Years 100000 miles.
If the dextron is weak than you will have no heat. Also check your
thermostat and make sure you change your fluid every three years.
A radiator flush helps. Some of the new TrailBlazers get really hot
93 degee's and up there. My 96 Blazer gets up to 90, even after its
been running for over an hour.
At 78000 I had the dextron replaced had a flush and replaced the
thermostat. The heater core was fine.

I am goung to try that tomorrow, can these things have an effect on where the air is blown out and the unresponsiveness of the control dial. Until I found this forum, I feared that the control panel was bad, and figured that it couldn't be cheap.

OK so I flushed, repaced the therm, and replaced the cap, but still no luck, I think it is either a vacuum issue or the door that controls the hot/cold controls (is this vacuum actuated?) and how can I check/resolve this issue?

Thanks for the help, got it working, hope to be a help to others

How was the problem resolved?

i have a 98 blazer and the heater blows cool air and i just wanted to know what can i do because winter is starting and it gets cold in ohio thank you

as every body has mentioned, i changed the cap,therm., and flushed the system. When I first flushed the heater core was so plugged that NOTHING was pushing through. on the second flush I disconnected the heater core hoses and flushed that seperately. This is what seemed to fix the problem (no I didn't listen when somebody suggested it earlier) but a whole pile of gunk came out and after refilling the system and getting the air out I have more than enough heat. As to the vacuum leak I thought I heard, I simply took the dash apart and the heater controls out and put it back together and that seemed to fix it (loose line?)

You can, once the engine is warm, feel the return line from the heater core and feel the difference from the inlet line. If there is a big difference, then you most likely have a blocked heater core. The next step is to disconnect the lines, put the hose on the end on the return line and try getting water through it. With both lines disconnected, water shoud be flowing out of the other line, without to much restriction. If water is just trickling...you have just confirmed a blocked heater core.