When heater is turned on there is no heat to the passenger side, blows cold air

Tiny
ZANDER_83
  • MEMBER
  • 1996 OLDSMOBILE LSS
  • 195,000 MILES
Prior to this issue I had loose cable connections to the battery. Recently after correcting the problem my climate control temperature display starts flashing for a while after starting the car, eventually it stops. While my wife was driving the car we had turned the heat on because it was getting cold and I noticed that while the driver side was nice and toasty the passenger side was rather cold. Even though I had set the passenger temperature to as hot as possible it was blowing cool air. What could my problem possibly be?
Saturday, November 2nd, 2013 AT 5:40 PM

2 Replies

Tiny
MADMIKE1735
  • MECHANIC
  • 951 POSTS
Upon some digging I found this:

Vehicle Application:
1996 LSS 3.8
Customer Concern:
Lose temperature control for the passenger side at times. OK now. The temperature indicator is flashing, when the condition is present.
Average Reported Mileage:
124000
Tests/Procedures:
1. With a capable scan tool, go into Heat Vent Air Conditioning (HVAC) system, check for codes.

2. Code may provide a direction to pursue.

The most common part failure is the HVAC programmer. Without having it verified bad, its a shot in the dark. I hope this helps.
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Saturday, November 2nd, 2013 AT 6:31 PM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
More then likely you have a failed actuator inside the dash. The heater AC bi level valve is the most likely cause. This controls the door in the HVAC system that directs the air to the proper area of the distribution box.

I attached the process on how to replace this. Before you replace the valve itself, we need to unhook the vacuum line going to it and hook that to a vacuum gauge and operate the system. If there is no vacuum then the line is the cause as there are no other issues then with this actuator.

Please let me know what questions you have but based on what you are seeing this is most likely the issue. Thanks
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Friday, April 17th, 2020 AT 4:35 PM

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