850 GLT Wagon - 1996 - Climate Control seems too cold

s2zeller · Post by **s2zeller** » 09 Sep 2009, 19:14

Off and on for the past several months, it seems like the climate control system pumps out too much cold air.

I try to minimize the need for AC by putting the internal temp a few degrees above what the exterior temp is (I'm basing the exterior temp on what the temp readout by the clock says).

Most times (see below), this seems about right.

Since I park outside all day, I often leave the temp controls for both driver and passenger at 84 degrees F for when I start for home after work.

Again, most times this works.

However, today - when I started the car - cold air pumped out (stronger on the driver's side vents) and continued for several miles until becoming less forceful but still cooler than the outside air.

Now, this was an extreme case of what more routinely doesn't seem quite right.

During the usual act-up, the temp controls seem to have no effect (as I increase the desired cabin temperature) until I hit 6-8 degrees above the exterior temp. At which point, warm/hot air starts to pour out.

I dial it back down, then the air is quite cold.

As I mentioned, the volume of air seems greater from the driver's side vents.

Also, I noticed that the passenger side seems a bit closer to right (i.e. not as warm when the air coming out seems too hot and not as cold when the air seems otherwise too cold).

Both sides seem to be affected by turning just one of the temperature control dials as well, but I'm not sure if that has always been that way or not as we usually just keep them the same.

I have - on rare occasion - noticed some flashing of the AC lights on start up, but nothing lately.

Post by **Ozark Lee** » 09 Sep 2009, 19:32

Welcome to MVS,

Let me noodle on your problem this evening and I will try to put together some things to try in the morning. Are you getting fog out of the vents?

...Lee

Post by **RobTheModd** » 10 Sep 2009, 07:05

s2zeller wrote: However, today - when I started the car - cold air pumped out (stronger on the driver's side vents) and continued for several miles until becoming less forceful but still cooler than the outside air.

As I mentioned, the volume of air seems greater from the driver's side vents.

I have - on rare occasion - noticed some flashing of the AC lights on start up, but nothing lately.

First parts seems odd seeing as how the blower is on the pass side... So if anything it should be blowing strongest there. like the vent closest to my blower blows like hell. so I usually close it and tell anyone in the seat to open it if they want more air. possibly something blocking or clogged up on the pass side?

Hmmm... The last part there with the blinking lights seems famil.... As lee once said... means its mad about something. haha. Mine was just the connection was lose on the blower, so fan cannot pull full power... *currently fixing btw lee. lol ill give you an update if I run into a prob* sooo it could be anywhere.

Trust me! from someone who has been in and out of the AC system on an 850 in the past month. ITS ALOT EASIER TO GET TO THEN IT SEEMS!!! haha. and listen to lee he knows things!

far as everything else. I sometimes experience sim things.
and the cold air thing... So glad I live in FL!

Well thats my 2 sense.

FCPEURO · Post by **FCPEURO** » 10 Sep 2009, 07:18

Just out of curiosity, why don't you just turn the AC off when you don't need it? That is what I do and then I can set the temp. to whatever I want.

s2zeller · Post by **s2zeller** » 11 Sep 2009, 07:21

I have the settings on AUT and - being something of a single-tasker - am operating under the principle of that just twiddling the temperature controls will get me what I want without having to do too much that distracts from driving.

So, am I ignorantly causing this apparent unexpected behavior by doing my temperature control that way?

The interesting thing I've noted the last couple of days is that the temp seems cool (even when I start with the temp set at 84) for about 35-40 minutes, then all of a sudden it cuts out and the cabin starts getting warm.

If I dial the temp control down (usually 4-5 degrees), then it suddenly starts gets colder. Go back up, and out comes warm air... which actually seems to be closer to how it should be working given the exterior air temperature.

So, this is more of a puzzler than a true inconvenience.

It is definitely a stronger flow on the driver side.

As far as the flashing lights, I have not seen any for 6 weeks or longer, I'd guess... and when I did see them, it would only be once on start-up and then not again for several more weeks.

And no, I've not noticed any fogging (had that happen in my VW Jetta).

Not knowing much about the intricacies of the system, I was wondering if this is
a) some sensor that is intermittently failing/dirty
b) a sticking flap somewhere
c) something that needs to get warm (or would 35-40 be too long) before it changes behavior.

FCPEURO · Post by **FCPEURO** » 11 Sep 2009, 07:57

I would just flip the switch for the AC to off and see what that does. When it is in Auto, it seems to turn on and off every few minutes so that would explain the hot then cool then hot again.

Post by **RobTheModd** » 11 Sep 2009, 08:03

Far as the knob thing goes...
Idk mine does somethign very sim to that. I really only get cold air unless I turn off the AC.
*Thank god for living in Florida* haha

My suggestion would be to wait for lee to help you out, hes pretty good.

But.. I would go with A if anything.
Lee... I cleaned connections. runs better now but its still struggling to pull power, *posting full descrip and some photos in original posting.*

s2zeller · Post by **s2zeller** » 11 Sep 2009, 14:49

FCPGroton wrote:I would just flip the switch for the AC to off and see what that does. When it is in Auto, it seems to turn on and off every few minutes so that would explain the hot then cool then hot again.

I'll give shutting AC to off to see what happens.

When in Auto, it is staying one or the other (*not* switching of its own accord)... except that it seems turn off at the 35-40 minute mark.

Post by **Ozark Lee** » 11 Sep 2009, 17:56

My gut tells me that you have an cabin temp sensor issue - it is common. There are little fans that draw the cabin air to the sensor just above the grab bars on both sides of the car. The fans clog up with lint and seize. It is a fairly easy fix once you get the grab bars off. A shot of compressed air to clear out the crap and then some lube for the blowers and you are usually good to go. I think we have some writeups in the repair database.

To be absolutely certain you need to have the codes read. On a '96 that means a trip to the stealership and a wallet weigh in to get the keys back.

I have never been happy with behavior of the auto settings so I control the fan speed and the air flow mode manually.

...Lee

s2zeller · Post by **s2zeller** » 11 Sep 2009, 18:48

One more day, one more data point...

As usual, I had the settings to AUT and the temp at 84 on both the driver and passenger sides. The exterior temperature was reading about 79.

As I drove, I noticed that the air flow was decidedly cooler than outside and that it was gradually decreasing over time until I got to that magic 35-40 minutes into the drive.

At that point, the air flow essentially stopped and it seemed like the car was warming up.

While the reduced airflow from the driver's side vents (i.e. those on the far left as well as the left vent in the center console) was still a bit cool, I noticed that passenger side output was quite a bit warmer.

I reduced both temp dials to 80 and was greeted by a greatly increased blower noise. The output of the dash vents did not increase at all but the temperature in the cabin seemed to be rising rather quickly... with what little airflow coming out of the passenger side being quite hot indeed.

Dialing both down to 78, I was again greeted with very cold air out of the driver's side and minimal (if any) flow from the passenger side (what there was was decidedly warmer than the driver's side as well).

Thanks all to reading my descriptions... I'll be looking more into your suggestions and hopefully get into some diagnostic work this weekend.