Heater issue?

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Yngwytprik

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1998 5.7 2 door tahoe. When i got this thing the blower motor was stuck on high. Not many complaints since its winter but obviously i wanted it functional. So i ordered a new “climate control panel”. And threw a new blower motor and resistor in with it just to since there cheap parts. The heater blew good and hot with the faulty control panel but now that i put the new blower motor, blower resistor, and climate controls in the air blowing out isnt getting hot. Its warm but not hot. I checked all 3 actuators under the dash and all seem to be working fine threw all the options on the control panel. If i turn the temp knob to the cold side the air gets cold, turn it to the hot side i can watch the motor turn all the way hear the door move and the air gets warm but not anywhere near as warm as it was before i installed the new parts. That lead me to looking at the heater hoses, theres a little valve right before the fire wall with vacc lines running to it. I found a vaccum leak there, fixed it and still no heat. Both heater hoses are hot but one is a little cooler than the other. Heater core is hot. Why did it blow hot enough to crack the window for cold air 2 days ago but with these new parts it wont?
 

SUBURBAN5

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If you swap the old resistor or old panel does it get hot again?
 

Yngwytprik

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i havent tried the old resistor ill give it a shot though. And the old panel doesnt do anything at all now. Before the blower would blow on high with the ignition on no matter what. now the blower does nothing at all with the old one on any setting. Weird.
 

SUBURBAN5

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i havent tried the old resistor ill give it a shot though. And the old panel doesnt do anything at all now. Before the blower would blow on high with the ignition on no matter what. now the blower does nothing at all with the old one on any setting. Weird.
What module did you install? Ac delco?
 

Yngwytprik

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What module did you install? Ac delco?
Not sure on brand ordered it on amazon.
Do you need to disconnect the battery so that the actuators re-set?

Seems to be a big deal on the Trailblazer/Envoy forum. I don't know if the GMT400s are the same way.
Ill give it a shot but i have doubts since they all do there job, air goes where its told to, it changes from cold to “luke warm” and the recirculate works good too.
 

Yngwytprik

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After i drove it to work this morning i am wanting to blame the heater core. Ill try flushing it and if it makes it better ill order a new one.
I started it to let it warm up for about 15-20 minutes went to leave and it was still blowing slighlty warm air. Hopped on the highway to work and it got hot. Hot enough i had to turn it down to low to cool off. So surely its just having a coolant circulation issue. I stopped for breakfast and waiting in line (could just be in my head) but it fealt like the air got a little cooler at idle. As long as im driving it it blows hot though.
 

Yngwytprik

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Are you using a 195 thermostat?
Whatever is “factory reccomended” is what the genuises at autozone gave me. And they talked me into this “failsafe” brand. Supposedly if it fails at all it will stick open no matter what. Think I should change it out?
 
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