'99 Regal Dual Climate Control Driverside Hotter

Hello,

This is my first post to this forum.

Starting last year, when I run the A/C the driver side does not get as cold as the passenger side. I do not have automatic climate control, however I do have dual zone (driver/passenger) temperature control.

I have the factory shop manuals and thought that the issue was with the electronic motor that controls the driver side temperature door, but when I took off the motor and operated the driver side temperature door by hand the temperature does not get any colder.

Before I dig any deeper which requires the removal of alot more IP parts I wanted to see if anyone else has experienced this issue.

Thanks,

Bob O.

I have the very same problem. If you find out what the problem is, let me know, please

[email protected]

Nice to see that I'm not alone.

I'm going to try the brute force method.

I'm guessing that the driver side temperature door is not closing all the way because it is blocked by some obstruction.

I'm going to take off the driver side temperature actuator motor and put the temperature door in the middle position. Then I am going to take a mallet and or plastic hammer and give the unit a couple of well placed "bumps" near the temperature door to see if that knocks anything loose out of the way.

It that does not work then it's off to the dealership to see if they can diagnose the issue. Summer's coming and I don't want to be sweating over this problem!

Bob O.

Well, my brother-in-law has a friend that is a mechanic and he looked at my car and it was way low on freon(spelling?). He filled it up and said that isn't uncommon that one side blows out hotter that the other when the freon is that low. Maybe that is your problem, also?

Hey, that's probably it especially since bumping the air handler near the driver side temperature door did not fix the problem.

I have noticed that the force of air on the driver side is not as strong as the passenger side especially when I have it in Bilevel mode. That would mean that the A/C evaporator (the part that chills the air) could be partially blocked. However this is not likely considering it's location.

I'm going to the dealership on 6/7 for some other work and to pick up some parts not related to this issue. I'll bet a recharge will fix it.

Thanks for the tip!

Bob O.

Well I took the car to the dealership and they discovered that I was about one pound low on refrigerant in a system that holds two pounds.

The A/C is now blowing equally cool on both the driver and the passenger sides. I also noticed that the A/C compressor is a lot quieter. I'm surprised that my compressor was not cycling off and on due to the low refrigerant, but that does not matter now because it's all cool air for me.

THANKS!

Have same problem.Said I had a bad A/C compressor. Had it replaced. 60 day's later same problem. Will be taking it back to check compressor on 7/13/04 .Said something about evaporator....Will let you know ...camron

I recieved an e-mail from someone requesting that I post it on the message board in the hopes that others may benefit from it.

Dear TL

Odds are that you changed or disconnected your battery right before this problem occurred. In hooking up the new battery you could have hooked up the positive wire first, then the negative. In doing so you (and I) inadvertently caused a problem identified as reversed bias latch-up in the computers that control the doors that channel the heating and cooling air. I won't go into the physics of this phenomenon, the fix is simply to disconnect the positive lead from the battery and short it to the negative lead (chassis), this will reset the electronics. Reconnect the lead to the battery terminal, voila! You should be good to go.

If you take the car to a mechanic they will want to reprogram the car's computer, $$$! My way is free.

I am not so inclined to get a handle to log in and post my comments, since you posted your email address I am writing in hope that you will be kind enough to post this answer that others may benefit.



Best Regards,

Russell L. Heath
Development Engineer
Controller Development Group
Tyco Electronics Power Systems, Inc.
Mesquite, TX 75149

I took car to delar said the problem was a stuck temp door.Wants to remove dash to adjust temp door.Will take 2 days and $900... Disconnected battery will let set over nite and see what happens..camron

Russel,

Great info, thank you very much! Just replaced my battery and had this happen to my 99 regal (driver side blowing warmer than passenger side). Disconnected battery, recconected, all is well. Thank you, you save me a ton of$$$ and headaches.

This is a fairly commomn and costly problem with the 97-99 Regals. It has to do with the HVAC Controller. There is a TSB out on this and cost is covered under warranty.

See below:

HVAC Temperature Difference Side to Side and/or DTC B0361, B0441 Set (Replace HVAC Controller, Splice into Backlighting Circuit) #02-01-39-001
HVAC Temperature Difference Side to Side and/or DTC B0361, B0441 Set (Replace HVAC Controller, Splice into Backlighting Circuit)
1997-99 Buick Century, Regal

1998-99 Oldsmobile Intrigue

with RPO CJ2

Condition
Some customers may comment on a temperature variation between the left and right hand ducts. Typical concerns may include that the right side of the vehicle cools down but the left stays warm or the opposite. This condition is sometimes associated by the customer with a recent service visit for other non-related repairs. The codes, DTC B0361 or B0441, may be present but will not illuminate a telltale lamp.

Cause
The HVAC controller unit and the TEMP door actuator motors rely on a feedback system that supplies the controller with count values in order to accurately adjust the air temperature. When battery power is interrupted to the HVAC controller, the current actuator position values are lost. When power is restored, the controller will perform a "sweep test" of the doors from full cold to full hot and record the end values for reference. Over time, the TEMP doors may develop some flexing when run to their extremes. This flexing allows the count values to run out of range (beyond 0-255) and results in DTC code B0361 or B0441 to set.

Correction
A revised HVAC controller has been released with new programming that allows for a wider tolerance in the expected range of the TEMP door. Replace the controller using the procedure below:


Important
On the 1997 Buick Century and Regal, additional steps are required. You will have to run a jumper wire to the new HVAC controller. Be sure to follow the additional 1997 model year steps below.

My 99 Regal has had the entire AC replaced including the auto climate control box in the dash. Still intermittant problems with the controller reading external temperature. It reads low, intermittantly by 20 degrees. Then the AC doesn't blow cold. Of course it works fine for the dealer. Another appointment, Friday, with photos of the external temps..67 and 15 minutes later 85. Last Friday driving to south Florida external temp 62 (real temp 92).

My 99 Regal has had the entire AC replaced including the auto climate control box in the dash. Still intermittant problems with the controller reading external temperature. It reads low, intermittantly by 20 degrees. Then the AC doesn't blow cold. Of course it works fine for the dealer. Another appointment, Friday, with photos of the external temps..67 and 15 minutes later 85. Last Friday driving to south Florida external temp 62 (real temp 92).

Has the outside air temperature sensor been changed? It is located behind the front grill area on the right side of the vehicle. Looks like a black christmas light with a wiring harness in the bottom.The HAVC control head uses this sensor to receive information on ambient air temperature.

I had a similar problem with my 99 GSE and replaced the sensor GM PART # 10248414. The system then performed as expected. Cost for the part was approximately $10.00 at the dealer.

The dealer, of course, couldn't get the AC to act up while at the dealership. They have it over the weekend. Lucky for me I have a second car to run around in. Thanks for the information on the part #, I may just change it to see if it helps. For $10 I can afford it.

i had the same problem...many times my low pressure hose was leaking...every time i had the system charged the a/c worked for about 1 day ...as it lost pressure the drivers side was warmer and passenger side stayed cold...when all freon leaked out both sides were warm

Well, my brother-in-law has a friend that is a mechanic and he looked at my car and it was way low on freon(spelling?). He filled it up and said that isn't uncommon that one side blows out hotter that the other when the freon is that low. Maybe that is your problem, also?
yup..happened to me. It was low :)

To fix this especially if you were working on the electrical system like I was (disconnected the battery) the problem is the computer needs to reset. To do that connect the red positive cable to the positive terminal on the battery. Wait 30 minutes to 1 hour then connect the black negative cable to the negative terminal on the battery. You can then test to see if cold air comes out both sides. When you start the car for the first time the time on the radio will need to be adjusted and the climate control head unit will start in the AUTO setting somewhere in the 70-78 degree range. You will need to drop the temperature to 60-65 to see if the air is getting cold on both sides. The reason I mention this is because I thought it was still messed up but then I looked and saw that once the climate control was reset it was no longer on the 60 degree temperature I had it on but was at the reset value of 75 degrees which is heat.

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