HVAC

Hello,

Starting to warm up here in Dallas and turned the AC on yesterday..... The four vents on the passenger side blew cold air but the center two and driver side door just blew vent air... Anyone else ever run in to this?

thanks,

Redline

Yes, you're seeing how the vents are divided between driver & passenger control, and you have a stuck blend-air motor on the driver's side. Get out the factory manual if you have one, and search this site for more info on both "hvac" and "climate control".

Oh boy...If one of your mode doors is stuck, get ready for some fun! Hopefully it's just the driver side actuator that is located behind the dash on the plenum (removal of knee bolster, console, IP and trim plate). If not, be prepared to dismantle half of the vehicle. The HVAC case is one piece and cannot be disassembled unless removed from the vehicle. Chances are, it's just the actuator, but if the mode door is stuck internally.......take a week off work and have a plate full of drugs ready. I can't even begin to describe the pain....

There is write up on here for the actuator replacement. It is common on these cars to have an actuator go bad occasionally.
The write up I remember seeing had some good pic's of location of actuators as well.
Randall was able to get a stuck actuator to work again by apply 5V to it with a small battery pack he made up and it's been working fine since.
There are a total of 5 actuators on the center HVAC plenum and another one mounted up in the passenger side of the car for the passenger's separate climate control.
I had the exact same problem you are experiencing, hot air on Drivers side and Cold air on passenger side.
The actuator that controls the Cold air coming out of the drivers side vents is actually located on the passenger side of the HVAC plenum in the center stack of the car.
An FSM can be helpful in doing this job as well.
My car was still under extended warranty when it went out but did talk to the Tech who replaced it and told me it was indeed on the pass side.
Doesn't sound right but that is the one.
There are 3 located on the drivers side of the plenum and 2 on the pass side of the plenum.
Here's a LINK to one of the write ups'
https://rivperformance.editboard.com/interior-f20/write-up-hvac-assembly-t2500.htm#27279

From what I remember only the glove box needs to be removed to access the actuators on the passenger. That and some gymnastics were involved.
To determine which one is bad you need to operate the system from hot to cold or vise-versa and feel for the actuator that is working and the one that is not.
If I am incorrect about it being located on the passenger side then the access to the drivers side actuators is not too difficult either. But from my previous experience I would start on the pass side.
Good Luck and please post in the LINK above what you find out so we have access to your experience doing this job all in the same place.
HTH

Rickw wrote:

The actuator that controls the air coming out of the drivers side vents is actually located on the passenger side of the HVAC plenum in the center stack of the car.

Just goin by what Mitchell told me....

According to the '98 manual, the driver's air-mix motor is on the driver's side of the climate control case.

Unfortunately, it also says that everything down to the instrument-panel carrier have to be removed...

Eldo wrote:

Unfortunately, it also says that everything down to the instrument-panel carrier have to be removed...

Plate full of drugs my friend, plate full of drugs

I am truly surprised no one here is aware that a low refrigerant charge can cause the drivers side to be warmer then the passenger side.

Before tearing into the actuators it would be easy to put a set of A/C gauges and see if shes low.

Well, I do know he replaced an Actuator on the Passenger Side of the plenum and it took him 1/2 hour and that's all the labor that was charged to the job.
He was a GM Tech that had done them before, so he didn't have to fumble around.
And I knew it was the right side before I even talked to him about the job because all my glovebox contents were in the trunk.
He forgot to put everything back. But I did discuss it with him at some length out of curiosity. I was surprised it was located on the passenger side and that it only took 1/2 hour to do. But he also mentioned you do it semi-blind. Most of it is by feel, as far as actually swapping out the actuator.

98inSFl wrote:

I am truly surprised no one here is aware that a low refrigerant charge can cause the drivers side to be warmer then the passenger side.

Before tearing into the actuators it would be easy to put a set of A/C gauges and see if shes low.

I wasn't aware of a radical temp difference when the charge is low.
When these actuator's stop working you have full heat coming out of one side and full (ice) cold coming out the other side. There's no mistaking that.
But if you are getting warm air from one side and cool air from the other side then a freon charge could be the solution.
I do believe you should hook a set of gauges up to the system, as you say, for a proper diagnosis.

Abaddon wrote:

Eldo wrote:

Unfortunately, it also says that everything down to the instrument-panel carrier have to be removed...

Plate full of drugs my friend, plate full of drugs

You don't have to tell me twice! I replaced my fuel level sender today, which required 1 Robaxin, 1 Flexeril, 2 Percocet and 4 highballs...

I know this isn't the correct place to discuss this, but you did your level sensor again.?
Did you replace with a unit meant to fit something else or did you bend the tangs again.?

Redline wrote:

Hello,

Starting to warm up here in Dallas and turned the AC on yesterday..... The four vents on the passenger side blew cold air but the center two and driver side door just blew vent air... Anyone else ever run in to this?

thanks,

Redline

Rick, I was not referring to a problem that pumps out hot or heated air out the drivers side, just when its vent air out the drivers and center, common on most dual air GM products to behave like this when low on freon.

IF someone is experiencing HOT not vent air from one side when commanding cold on both thats a actuator problem!

P.S.
I just replaced my leaking compressor, it leaked out every 3-5 days, I was filling it for 3-4 weeks before the new compressor was installed, low freon resulted in vent air from the left and center vents 1-2 days before the right vents warmed up.

Thanks for pointing out Redline's statement. I read too much into it. Without reading it slowly.
Your right about vent or warm air.
I also had to replace my compressor, after the actuator problem. Quite a long time after the actuator problem actually, so the two different problems were not confused. And I am now aware of the two different problems that can exist. Sorry for the confusion on my part.

Actually my compressor started leaking at the the compressor seam or joint where the compressor is bolted together.
Got a New Comp., Receiver Dryer and orifice tube/filter, also out of my wise purchase of an extended warranty.
For what it's worth, I bought the car for cash from the original owner, but had the feeling that i better buy an Extended Warranty on my own and I'm glad I did. Because in addition to what we have already discussed I have had the Transmission rebuilt, Alternator replaced, etc.
Much work was accomplished the first two years i had the car and got it with only 76,000 miles on it. But had the trans done around 82K and so forth. Got more than my investment back on the cost of an Extended Warranty.
I talked the original owner down $2,000 from what he was asking and spent $2,000 in the first month on the Ext. Warranty and having the hood repainted and new brakes (EBC), struts and springs and some other non-covered item's. So I ended up paying what i wanted for a clean Riv after all was said and done. And I now have a clean two owner Riv with all new parts.

Shoot I did forget to mention my compressor was replaced because of a large leak in the same place as yours.

No warranty here, just had the antenna quit tonite, , just changed the tranny fluid,ditched the dex cool ,soon to replace the original front brake pads/fluid and P/S fluid 49,500 miles

That's the problem you changed the tranny Fluid, it's a known cause of Antenna failure.!!!!

I knew there were possible ramifications but didnt put that together

Thanks for all the help, just got back in town today.... I'm going to check the coolant first, seems to be the least of the evils!!

Mike,did adding Freon fix you up?

Not yet, but I think there might be a few other problems....... Cold air is coming out just to the left and under the glovebox. ALL the time if I have the air on...

Actuators...

There aren't any vent's under the glovebox that i can remember. So it would have to be a disconnected duct behind the dash somewhere, maybe.

ya this weekend I'm going to craw under there and see if something came loose, I had the car washed the other day and when I went to leave I noticed a lil blue tab in the floorboard under the glove box...

98inSFl wrote:

I am truly surprised no one here is aware that a low refrigerant charge can cause the drivers side to be warmer then the passenger side.

.

Why?

Albertj

Why does that happen? I believe the evaporator coil in the dash is divided top and bottom for the left and right(respectively) dual zone air.
When low on freon the top of the evaporator is not filled with freon as well.

All I can say with certainty is I have seen this on caddys, impalas , monte carlos , topping off the freon fixes the VENT air on the left and cold air on the right.

Anyone else have a differing theory ?