'01 3L X5 - A/C cold on driver's side Hot on Passenger's side
 

Hi guys,
the title says it all, A/C blowing different temp: Driver's is cold and passenger's is warm. And yes, the temp setting is the lowest on both sides, and the temp dial on dash is set to 3 blue dots.
Any ideas why?

sounds like heater valve stuck open; i've seen the same on a recent X5 i checked out pre purchase for a friend (he opted not to buy). With a quality scan tool you can read the real-time heater core temps. If not that, a bowden cable on the temp control vane would be my next guess.

I use heat + AC all the time when it's raining out; when the car is up to temp and you have climate control holding the temp steady you should hear what sounds a bit like a heart beat as the valves open and close to the driver/passenger side of the car (with radio off of course so you can hear it). with one working the beat will not be the 'lub dub' sound but just a 'dub… dub.. dub… dub' sound as only one valve flipping on/off. The valves should be right between the engine and firewall, you can likely feel the hoses and determine one is not closing and staying hot.

Andrew, when you say a heater valve, do you mean one of the two valves from the heater control valve?

it would be weird to have one side cold from a low 'freon' situation, but define 'blows cold'… cold means it's at least 15° colder coming out of the dash than in the cabin; i usually see numbers like 40 to 50F coming out; get an actual objective reading of the left vs right side. If you have 60 and 90 that's a big difference of 40 and 90. (weak vs broken)

Yes. If one of them is stuck open you'll get the symptom you describe.

My scanner will show both the valve position and heater core temp but hand on each heater hose will tell you

What scanner do you use?
If you don't mind me asking..


Mine also blows a little hotter on the passenger side, and curiously my Volvo just started to do the same..
And I read yesterday on a Volvo forum that low charge may cause it, is not a big difference, but yes you can feel it.

Since I just replaced the X5 compressor I will report, maybe tomorrow if the new recharge, took care of the problem...

Foxwell NT-510 (520 would be the same but also covers mercedes; so get that if you also have that brand).

I HATE the idea of pulling out a computer to work on a car and hate the idea of using software written in the 20th century almost as much as I hate the clumsy operating system required to use it so I researched how I can get to most things without using the sloppy system most use.

It takes a good long time like ten minutes for a full scan but you get a very good picture of what's been acting up on your car over the past 10-17 years since the last real scan. I ran on wife's car a week ago and cleared about 15 codes mostly related to low voltage.

The 510 will activate systems and report real time values such as what's the pressure of the brake lines or temp of the heater cores.

Awesome!!

It fixed the problem for me...

Now, the reason I changed the compressor, was because it was taking some time to kick in, but when the AC was working there was a slight difference between the passenger and driver side.
But now after the new recharge the problem is gone!