AC/ heat problem

[jpmaniac87]

I got a problem on my 2000 LS... Actually two problems but i think they are related...

When i turn on the heat in the front, it's nice and hot, so hot i want to put the selector to blow cooler air. well, when i move the temp nob to cold, it keeps blowin hot air, as if it's stuck. the only real way to fix this is turn the tahoe off while the blower too is off, and maybe, just maybe the next time i got to turn it on, it will blow cold. that's one problem.

the second problem, my blower fan for the AC/Heater only works on setting "3" "4" or "5" but doesn't blow on "1" and "2". The compressor kicks on for it to produce cold air (i know this cause when im driving, i can put it on either of these and the non recir mode and feel cold air).

If i get a new control unit, will this fix both problems?? any ideas??

 

[speedr1023]

there is a clapper valve behind the dash that should switch between hot and cold air. That valve is probably stuck and thats why you are only getting the hot air. That happened in my mother's 99. Maybe someone else can explain it better.

 

[jameym00]

It called the Mode Door Actuator. That could be problem, its located under the glove box near the tranny hump, or its a blower motor resistor. Normally when the resistor blows you will only have heat on med or high and not low. I would try the Mode door actuator first, there are two of them one for hot and cold and then fan speed. They open and close the doors in the heater box

 

[jpmaniac87]

what's the best way to get to it? You think i could just clean all the parts instead of buying a new one? cause it costs like $30

 

[road1will]

if its only $30 just buy a new one...

 

[jpmaniac87]

Well... Poor college kid...

 

[jpmaniac87]

And what is the best way to narrow the problem down as to which part it is?... without just buyin both...

 

[jpmaniac87]

Alright, found the problem, its both of those. When the blend door gets stuck, i can unplug it and plug it back in, haha, but i will be getting both the blend door accuator and the fan resistor pack to fix my problems. Thanks for the help

 

[jpmaniac87]

Alright, so i ordered the part (blend door actuator) from RockAuto with the same pin configuration i have, got it, and installed it... it went to hot mode and then quit working. i put the multimeter on it and it seems like the connections are all good... so i put the old unit back in and its kinda working, i just have to unplug it time and again and replug it to make it go back to cold... any ideas what gives?? Did I get a bad part?? Please let me know ASAP so i can return this if it's bad.

 

[greengumby]

nope they have to be re-calibrated

 

[jpmaniac87]

Can I recalibrate it?? what does this entail??

 

[jpmaniac87]

The easiest thing to do at first is remove the "blower motor" fuse from the fuse box. Usually it's in the #1 spot and it's a green 30amp. Check your manual for proper location.

Pull this fuse out with car off, for 10 mins.

Install fuse, start vehicle for 5 minutes with Heater/AC off.


This should calibrate the HVAC system, specifcally the blend door actuator.
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Does this sound right??

 

[jpmaniac87]

ok, this didn't work... i need help bad! now the old one wont even work...

 

[jpmaniac87]

Figured it out, i think. When i was recalibrating, i was doing it with the actuator hooked up but not installed, this was putting the gears in a bind. it works now. thanks for all the help guys! and yes, i do feel kind of dumb now