So it continues. I decided to turn the heater on today just to make sure it works. The temp was up on the gauge so i blasted the heat. First i smelled what i figured is antifreeze and the heater doesn't blow very warm at all. a friend said water pump. I thought heater core.

Also, no matter what spot setting is on ( defrost, down below or dash vents) the dash vents always seem to be blowing air, more so when it is on that setting.

Also again, when ventilation control is off, i hear what sounds like a hissing noise. once you turn the dial from the "off" position the hissing goes away. thanks to all who answer. Hopefully down the road i can help answer some questions.

Brian

 

Can anyone help me on this one? At least the first question. Not too crazy on the smell of antifreeze. Winter is around the corner and when i pick up my 5-month old son after work, i think he may enjoy heat in the truck. lol. Thanks.

Brian

 

Seems to me u have a combination of problems. A smell of antifreeze in the cabin is most likely a leaking heater core ,have the systems pressure tested by a shop.You can do the work yourself but it does involve taking the dash apart.As far as the vents, could be a vacuum problem. Sound like the switch (Round Dial ) is leaking at diffrent positions.I will try to get u a schematic for the vacuum lines for u to check them but i looks to me its the switch. rockauto.com has those switches i believe. good luck

 

thanks 19blazer95. I just checked that site. They sell the whole module with all three dials for $77. is that the one youare talking about when you say "switch" or do you mean the individual dial that does the defrost, dash vent and such? the dial on the far right.

Brian

 

it could also be the blend door motor or the blend door itself. i kno fords have a problem with their blend doors messing up but never heard about blazers havin this problem but of course things do break

 

I put a new battery in my 98 with climate control and now the blend door cycles constantly from hot to cold. Any help out there?

 

Roy45693, read through this thread and you should be able to solve your issue.
https://blazerforum.com/forum/2nd-generation-s-series-1995-2005-tech-41/electronic-air-heat-control-continous-cycling-20633/

bman416, if your truck has the three separate dial switches then you should be able to just replace the one selector switch rather then the whole unit. It will depend on your make/year if you have three individual switches or if you have to replace the whole assembly. No way to know for sure till you remove the old one.