Heater blows cold air, defroster blows lukewarm air

Tiny
ALLENFROMCVILLE
  • MEMBER
  • 2006 CADILLAC CTS
  • 2.8L
  • V6
  • RWD
  • AUTOMATIC
  • 127,000 MILES
After having to replace the ECM and ABS modules on my 2006 CTS, the heater blows cold air and the defroster blows lukewarm air. The heater hoses are hot, and the thermostat is working fine (at least the water temperature is good). Wondering if maybe some kind of control valve, or maybe a setting in ECM?
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Monday, January 27th, 2014 AT 9:46 AM

9 Replies

Tiny
SATURNTECH9
  • EXPERT
Did you put used computers in?
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Monday, January 27th, 2014 AT 9:50 AM
Tiny
ALLENFROMCVILLE
  • MEMBER
Yes, they were used. The mechanic who installed took to the dealer to have flash programmed.
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Monday, January 27th, 2014 AT 9:53 AM
Tiny
SATURNTECH9
  • EXPERT
So the heat worked and defroster before replacing the computers?Also thats strange to have to replace two computers at the same time.
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Monday, January 27th, 2014 AT 12:32 PM
Tiny
ALLENFROMCVILLE
  • MEMBER
Wasn't at same time. Strange situation. ECM changed out, then had code for ABS. Changing both worked. Everything else fine. Someone had hooked up battery charger to battery while still in car :-(
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Monday, January 27th, 2014 AT 12:37 PM
Tiny
SATURNTECH9
  • EXPERT
Was the polarity correct when the charger was hooked up?Also did the heat work before the battery was charged?Has the ac computer been scanned for codes yet?
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Monday, January 27th, 2014 AT 2:52 PM
Tiny
ALLENFROMCVILLE
  • MEMBER
Polarity was correct.
Heat worked fine before modules changed out.
Didn't even know there was an AC computer, so no it
has not been scanned. I assume this is something that has
to be scanned separately?
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Tuesday, January 28th, 2014 AT 6:34 AM
Tiny
SATURNTECH9
  • EXPERT
Yes you have a auto climate control correct?If so you would need a professional scan tool not a diyer scan tool or free auto parts scan. One that can read all the computers in your car. You might even need that scan tool to diagnose the problem.
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Tuesday, January 28th, 2014 AT 7:49 AM
Tiny
ALLENFROMCVILLE
  • MEMBER
OK.I have a friend that has one for his body shop. I will see if I can get him to scan. Thanks.
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Tuesday, January 28th, 2014 AT 8:06 AM
Tiny
SATURNTECH9
  • EXPERT
Your welcome keep me posted.
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Tuesday, January 28th, 2014 AT 9:57 AM

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