Display on the climate control not working

RON MCCOY

MEMBER
1999 BUICK REGAL
TURBO
225,000 MILES

We had a small electrical problem on the window portion underneath the seat and fixed it. I'm a technician and every connection was re-soldered. We have everything working but we do not have display on the climate control. I replaced it with a new unit and still do not have any display. Every connection and he has been checked as well as all contacts cleaned with an electronics cleaner. How can I obtain a power output for the Molex plug on the back connector? We bought a Chilton's manual but can't figure out voltages for this system.

2 Replies

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi,

I attached the wiring schematic I have for automatic climate control. If you have manual control, let me know.

The first thing I question as a problem is a splice. There is a splice in the ignition power supply to the controller. I highlighted and circled it in pic 1. What I suggest is to first check the HVAC fuse in the fuse box. Make sure the fuse is good, tight, free of corrosion, and there is power to and from it. Here is a link to help:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

If the fuse is good, then go to the controller and locate the brown wire (C5) and see if there is power to it when the key is in the run position.

I have a feeling there is an issue with that splice in the ignition power supply.

Let me know what you find or if you have other questions.

Take care,

Joe

See pics below. Note: The schematic was two pages long. I had to cut each one in half to make them readable for you. However, I did overlap them so you can follow from one to the next. Additionally, I highlighted the wiring involved.

Images (Click to make bigger)

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Sunday, September 19th, 2021 AT 6:58 PM

ATARAX

MEMBER
7 POSTS

Hey, I have similar problem. I have a 2004 Buick Regal LS and there is nothing on the climate control screen. Sometimes the red warm dual lights only lights up (bottom right see attached picture). At nights the light of some buttons light up, but there is nothing on the display. One day, I started the car, the screen came on just for a sec and then nothing. When I tried to set the temp it turned off. So far, all the controller does is blow a little of hot air only (randomly). I turned the key to on. I measured voltage and on C5 and I got 3.15V. I checked the 10 fuse (was ok), but I changed anyways. I was trying to trace the brown wire from the cabin fuse box (Second picture). I measured voltage on third picture for C5 and I got the same reading 3.15V. I was traying to locate the S233 splice but did not succeed. I just have basic car wiring knowledge. I also unplugged the relays from the engine fuse box, I tested resistance and apparently they are ok. Following this procedure: https://electrouniversity.com/how-to-test-a-relay-with-a-multimeter/

Finally, I was reading other posts and I also have the same issue with the cruise control, (mirrors are working though).

https://www.2carpros.com/questions/buick-regal-2000-regal-cruise-amp-fan-system-stop-working-same-time

The post explains the reason is the ignition switch, but it seems a job for a professional.

Not sure what to do, to be honest.

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Wednesday, August 21st, 2024 AT 4:56 PM