I have a 1997 S90. I bought the car new. The air conditioner has always cut out under heavy acceleration. Yes, I know it is designed that way. I would like to disable this feature. I live in Austin TX and in the summer it is quite annoying to lose my air conditioning when I accelerate or go up hill.

I almost exclusively use the car in town now. When I used the car on the highway it was not an issue, but in stop and go town traffic, especially in the hilly area that I live, it is a problem.

Is there a simple, or even fairly complicated way to disable the feature. I am retired high tech so working with electronics is fine with me.

Thanks for your help.

Bill

 

Hi Bill, I don't think my 960 does that. Have you check the pressure in the system to make sure it doesn't need servicing?

 

I believe that most vehicles have this feature; when you go WOT the A/C cuts out to divert all power. If I remember correctly it has to do with the PCM reading the signal from the sensor on the TB and when the TB shows WOT it disables the A/C.

 

I have not checked freon levels but the air conditioner blows cold air when throttle steady or at idle. The Air Conditioner cuts out under heavy throttle and the blower slows down when under intermediate throttle.

Any ideas would be appreciated.

 

I'm to cheap to push my throttle often. I usually only floor it to get out of someone's way or to avoid an accident, but I still have not noticed any blower lag. My guess is that it's a vacuum problem. The old 740's have some vacuum billows behind the firewall inside the car that would crack and cause a simular problem. I hope that's not it but look into vacuum.

 

I would also agree with a vacuum problem if your blower isn't working properly. A/C cutting out under WOT is normal, but only under WOT not just normal or even spirited driving.

 

Thanks folks for the input. Any ideas on troubleshooting the vacuum system? Any way I can see if there is a leak without taking the dash apart?

Bill

 

Not sure how you can test it.

 

If the A/C runs off of a vacuum unit in the engine bay you can test that very simply. Any mechanical vacuum gauge will do, you just need to determine where the vacuum source is and make sure there are no leaks.

 

Same problem I seen in my car's A/C. On that time just repair it with the help of mechanisum. How long mouth ago you repair the parts of your car and its parts, I hope their is nothing problem is your A/C, just service it at once.

 

I serviced the freon on the A/C. The system was if pretty good shape but I topped off the freon any way. The system was cooling well when it is on so I expected that the freon charge was not the issue.

After top off there was not an appreciable change, the A/C stops when I accelerate.

Any more help would be appreciated. I have not done a thorough test of the vacuum system yet, but it is next on the list.

Thanks for the help so far.

 

I have the same problem. My air is cool but it doesnt blow hard and when I accelerate almost no air comes out. Anybody have any other ideas? Its really hot in Georgia and I really need to fix it. Thanks

 

There are several possibilities.

Does the blower fan's speed change accordingly when you select 1 thru 4? Does the air-flow change direction when you accelerate?

What are your refrigerant pressures?

 

Looks like no one cares but in the OPs comments he mentioned that both the compressor kicks out and the blower fan speed drops off.

The clutch should only cut out at WOT and the blower to the best of my knowledge isn't affected but when I plant my foot to the floor the blower is the last thing I'm thinking of.

I'm wondering if he's having a problem with the amount of voltage/current and for some reason it's dropping low enough for the AC clutch magnet to lose hold ??

 

Unusual symptoms, but a couple of comments from my experience with 16 years on our S90.

The A/C magnetic clutch assembly does wear over time (our earlier Ford Taurus was much worse for this) and the fix is to pull the outer plate that actually drives the compressor and adjust it. The clutch is designed for a small air gap when not energized and with wear from cutting in and out the gap gets too wide for the magnet to pull in the outer plate reliably. The fix is to change the spacer washers to decrease the gap (Volvo sells several washers for this).

In general I've seen this show up with the A/C working fine when the car just starting cold, but it will stop working after some driving on hot days (when you really need it). The clutch design on our Taurus (Nippon Denso compressor) was so bad that I had to re-shim it about every 20k miles vs once on our S90 at about 100k miles. On both the Taurus and the Volvo this can be done without removing the compressor, so no need to purge the A/C system, etc. Note, on the old cars the compressor was engaged once when the A/C was turned on instead of the current system that cycles the compressor to save fuel. Simply observe the compressor cycling and consider how many times the clutch cycles for each mile driven.

With regard to vacuum leaks, these caused me a lot of trouble with getting the OBD monitors to complete their tests as required before CA will do a SMOG test. After finding a couple of bad fittings, I simply went through the parts book at a dealer changed them all (about $120 worth of Volvo parts). In general you need Volvo parts because the fittings often go from a line at one OD (blue plastic things, etc.) that connects to a actuator that uses another OD.

Getting back to the original problem, I note that there are several of these fittings associated with the A/C, in general located above the receiver/dryer and there are also some check valves (little plastic things) in the area as well. To see how bad these might be, just feel a couple of the fittings for the A/C as those in our our car would simply crumble after 10-12 years in the LA air. Without vacuum the A/C probably will not open some of the internal flaps that adjust the air outlets as requested by the automated control (or possible you get a "none" state).

 

Bob_fromLA, that's fascinating. I'm actually having that exact issue with my 2001 V70 - the AC works ok when the car is cold, but within a few minutes it shuts off (seems to quit faster the hotter it is outside). What I've found is that I can turn off the AC (hey, it isn't working anyway) and after a few minutes if I turn it back on, it will work again for a short period of time. If I don't wait long enough, it won't re-engage. I wonder if this is the same issue...

At any rate, if I were to check into this, how would I go about determining whether the air gap in the compressor is too small and needs to be shimmed? Is this something worth doing myself? I have a set of gages / recharge manifold, and the refrigerant pressure seems to be okay...

 

Here is some info on shimming.

https://volvoforums.com/forum/volvo-...shimming-6665/

http://www.matthewsvolvosite.com/for...hp?f=1&t=39209

 

Nice article on clutch shimming. If you find the right puller, at least on the S90, there is enough clearance that you do not have to remove the compressor (or even the belt) to replace the shims.