A/C blows hot all the time.

Hi,

I have looked around for info on this board and have come to some possible answers but would like your opinions on this.

The short version:

Car with flashing temp blows hot air even though the AC is on and the compressor is running.

The long version:

A friend of mine has a 96’ Bonneville SE. It has an auto climate control (has a display with a Mode button and a temp button to the left of the LCD). The problems started happening a year ago. The first was changing from the vent to defroster ( during heavy accel. We found the vacuum line was broken at the canister. Later he started getting it to where it was always stuck on defrost no matter the setting. That time it was the nipples on the box under the right side of the glove compartment. (I understand what it is but don’t know the nomenclature). Then problems with the clutch relay socket. Then it started flashing the outside temp. I understand this is a fault code, but can’t find any info on how to get into a diagnostic mode or read the code. (From the info I found it was said that it is not possible after 95’ but the post was a 2003 post).

The head unit in the dash has been replaced with a known good one and we just got through replacing the control unit under the dash WITH the vacuum lines all the way to the actuators for the doors. When we started it up it worked “fine” but the Out side temp started flashing.

After driving the car out of the shop and parking in front it worked, after locking up and driving to my house (across the street), it worked. After we went inside and had a beer he went back outside and started it up and let it run for about 10 minutes. When he checked it was blowing full heater hot air. We tried shutting the car off and every other combination imaginable to make it blow cold air using the control panel. He told me that there is a positioning sensor on one of the doors but I didn’t look at it. It seems that the door (blend?) is stuck or is being “told” to stay in this position. The Compressor is running and the evap tube is getting cold, but it does cycle even though the temp is set at 60*

The question’* I have are:

How are codes read, or could someone point me to a thread I searched but couldn’t find anything other than take it to the dealer (which was done once)?

Does anyone (or again point me) to a source for the schematics for the system?

I know it could be the blend door from the pics I saw while searching. We haven’t tried that yet because we want to fix it right.

Thanks,

Jeff

Jeff..Let us say..good post.

Apparently you guys have done your homework, right down to the beer drinking part.

There is no way to read codes unless you take it to a dealer or you know of someone with a Tech2 scantool.

Best schematic and diagnosing (which would include using a tech2) would be from the factory service manuals which are typically produced by Helm. They can be found on Ebay usually at reasonable prices. Or possibly there is a member local to you with them. The diagnosis is probably too many pages to scan.

Probably not a blend door itself issue as much as a airmix door actuator aka blend door motor that sits on top of the programmer unit you switched out. You do remember plugging that little motor in right?

Lash did a little research and found this link to a calibration procedure.

http://www.bonnevilleclub.com/forum/...&highlight=ecc

Well I guess the Library is good for something after all since they have the Mitchell manuals, I’ll have to go take a look.

I guess the blend door motor connector that has about 5 wires on a 7pin plug? That real difficult one that is actually pointing down when installed? If that is the one then I got it in.

[rant] I can’t believe that GM actually made this so hard to troubleshoot. I remember on Cadillac’* and Camaro’* there were adjustments and options and diagnostic modes in the radio. I could get info out of the climate control on the Supercoupe, and I even read that you were able to read codes prior to 94’ on these cars. Good going GM, make a 10 year old car nearly impossible to work on [rant/}

Well at this point I have at least 1 friend with a TECII tool. I will see what I can do there. But in the meantime is there a way to drive the door to the AC side (we are in Hell, errr Houston)? Heater? We don’t need no stinking heater! Is there pot or some type of feedback device that would indicate in what position that the door is in? That will give me something else to check. Also what are the vacuum line color codes (which one operates which door) I know they are connected correctly but I just want to know and it’* kinda hard to tell when you are upside down and backwards.

Thanks for the info,

Jeff

Bill thanks for that info I will read it more in depth when I get a chance (gotta do some work )

One other thing that occoured to me is that we worked on the car in our shop which is air conditioned. The car was kept in the shop before we got off work. The air never blew cold just cool, we thought it was fixed (other than the flashing error). So I think given that the car was cold that the engine wasn't hot enough to blow hot air.

Thanks again,

Jeff

Ok..remember..you asked.

Wren'* Redneck Fix

OMG Love it. If this keeps up there will be a coathanger in the glove compartment.

Many thanks,

Jeff

Hightech or Lowtech...we've probably got a post with someone trying it.

And it still works. If it had been the SSEi, I'd have fixed it right. But the SLE is my beater. It'll get one when I have time to deal with it.

In the meantime, the rod suits me fine. That'* actually 1/8" brazing rod.

Jeff, did you get a chance toread through this thread yet? (Linked above)

It has both the reset procedure and the airmix lever recalibaration, if it comes to that. This is known to have worked for some here already. I agree with you that it would have been nice if our friends at GM would have left a diagnostic method available to those of us that are not brain dead, but I suspect there was some amount of dealership politics involved.

Edit: I got real busy while writing this post, so it'* almost moot now. Meh...