Hi All,

My daughter's 99' Blazer is not producing heat for the heater or defroster. The blower fan works and the mode selector switch seems to work as well. What should I check for and how would I fix it. Thanks for the help.

 

Check to see if both of the heater core lines under the hood are the same temperature once the engine is up to operating temp. If they are not, then you have a restricted core.

 

Hi swartlkk,

Thanks for your help. I will check it tonight when I get home.

 

Hi,

I am having the same problem with my 99 blazer. Both heater lines remain cool with the engine warm. Blower works too. Seems as though I have a restricted heater core. How do I resolve this? I hope I don't have to get to the heater core as that seems like a project, removing the dash and all.

Thanks,

Larry

 

The first thing is to attempt to flush the core.

 

I had a problem with my jimmy a couple of years ago,same symptoms as yours. I put a flush adapter on a heater hose didn,t work. so i held a garden hose on the heater core fitting ,and a big blob of slime came out of it, it has worked great ever since.

 

Well, my daughter came home long enough so I could work on her vehicle. It turns out it was about 1/2-2/3 gallon short of radiator fluid. Topped it off and it works fine now. Seriously considering flushing the system any way to be on the safe side.

 

Now you have to determine the cause of it being low. I would replace the cap as a first precaution.

 

pressure test the cooling system to check for leaks as well

 

Thanks swartlkk and blazer blaze13. That will be on my list of chores for this weekend.