My heat was working fine until I installed an in-line coolant heater for cold days..
When i slide my temperature to the warm.. NOTHING comes out of my vents on full fan.. on any setting.. but when I turn it to cold.. it blows cold air at me...

Before I go out there and much around.. any suggestions?

 

Are you getting coolant at the firewall?

 

Not sure on that one.. any way to check without making a big mess? lo

 

Don't have the engine turned on and it shouldnt make that much of a mess...

 

Man, I wish we had no heat down here in Georgia. We were over 100 degrees F again today, with no end in sight. But yeh, you've got to trace your coolant flow, sounds like it might not be going through the heater core. Or we could trade cars, mine has fantastic heat.

Ray

 

I wish I didn't have heat in my car. In fact, I'm about to recharge the A/C. It's "only" 101 here, in the shade. Take that, Tiger Woods!

If you have flow to/from the heater core, but not thru it, the core could be plugged up. I've seen a few that were so plugged, even 100+ PSI of air couldn't get thru.........

 

well in the middle of the night and raining up here.. its not exactly hot
i like cruising with the window open a bit in any weather.. and that makes it even less hot..

shouldnt i still get air blowing on "hot" mode? there is no airflow from the vents on full fan speed.. but when i switch to cold.. the vents blow like theres no tomorrow

 

"Hot" mode should blow towards the floor/windsheild. It can be directed thru the vents, on most models.
Can you hear the blower running? If so, can you feel any air blowing, anywhere?

 

It used to blow through the vents just fine.. on the hottest setting I cant feel ANY air ANYWHERE.. but the blower motor is indeed working... while its going.. i can slide to cold and TA DA! air is blowing everywhere

 

"My heat was working fine until I installed an in-line coolant heater for cold days.. "

OK, tell us more about this in-line coolant heater you installed. Sounds like it is the culprit.

 

exactly! what does it do and did you have to wire ito any of your existing wiring?

 

oh.. its just a little container with coils inside which heat the coolant system. it has input and output for hose.. its completely open so it shouldnt have problem flowing coolant... all it has for wiring is a cord with a plug on it.. like a "block heater" all the new cars have the cord sticking out by the headlight

 

but.. this is the part i dont understand... whether coolant is flowing to the heater core or not.. shouldnt the fan still blow SOMETHING? its almost like the "hot" side is clogged or something

 

check these two things 1) when you turn on the defrost does hot air begin to ambiently come out of the defrost vents (not blown out but the hot air is slowly rising out of there) 2) drive with the heat off until your car heats up, then turn the heater on... does your temperature drop...

If the answer to either of these questions is yes than your heater core is flowing properly... I suspect your heater core is working and your real problem is the blower.. the reason the blower could work with the A/C and not the heat has to do with the way the variable resistor in the blower was wired in some models... to see if this specific instance is the case try running your blower without the A/C on with the heat off (A/C selector off, temp selector at its coldest)... please post your results and I will get back to you...