When I bought the car last year, I reported on another forum that I had A/C freezing problems. You told me to change the low pressure switch, so I bought a new switch and the freezing problem disappeared.20 days ago I went to bypass the switch to test it and I saw that it does not have that metallic clip that the other Bosch sensors have, you know the one you press to release the connector. So now I am doubting if the mechanioc really chaned the switch or just went ahead and kept it and told me that he had changed it.

Does that switch have a lock or can you simply remove it manually by pulling? Beacuse if it does have a lock then the mechanic kept the new switch.

Tech, the blower works fine, and AFAIK so does the cooling fan. The car's temp is always where it's supposed to be, event with the crazy temps we have beengetting here lately. Are you suggesting that I check the cooling fan relay? How would that affect the a/c? Sorry for my ignorance.

The air that is blown when the a/c is off is just normal outside temp, not heater level temp.

 

Haha, loved the ASCII art.

Regarding the faulty ABS PCB soldering, also been there. When I bought the car the stealership gave it to me without documenting in writing that the ABS wasn´t working. Their mistake, stupid ignorants of consumer protection laws. I had a lawyer friend of mine call the owner of the stealership andtell him thatwe were not only going to sue them but that we were going to notarize the problem and post an add in the local newspaper saying that they were tricking customers and risking people´s lives by selling cars with faulty brakes. 20 days later I had a new ABS module installed for free. I also complained for a faulty evap valve and they also changed it.

The stealership manager called me and told me that the owner was really upset with the sales guys. Apparently everybody knew about the faulty ABS and they did not follow the correct procedure. BS if you ask me. There is no such procedure for that here. Employees are too ignorant, lazy and informal to study procedure, much less apply it.

He was also very curious of how I got hold of the owner´s cell phone number. I called so many times to complain that finally one of the administration employees, who hated the sales guywho had sold me the car, leaked all the info to me to get the salesman in trouble.

In conclusion, always always always complain, even if you know that it´s your fault for not checking thoroughly enough. Call them 20 times, threaten with sending your lawyer. Then send them a notarized letter (here that´s very cheap). Then have a lawyer friend call them up. You don't need to spend money, just exchange it for a barbeque or some help on his car or computer or whatever you know how to fix. Lawyers like bullying people, and showing off to friends, so they will probably do it for free.

 

Yes there should be a metal clip on the wiring side for the sensor.

If the cooling fan isn't working properly the A/C high pressure will get to high and turn the compressor off.

 

Hmmm... so if there is no clip on the side of the sensor then there might be loose electrical contact and intermittent signal to the compressor. Interesting... my mom told me she noticed that the compressor would engage/disengage when she pressed the brake (engine moving forward) or hit a bump (vibration). Gotta test it this weekend and see.

 

The low pressure switch has 2 sides: the bottom part connects to the freon line, and the top part has a male connector, which is plugged to a wire that that takes the low pressure signal to the ECC computer(?).

THE CONNECTOR WAS LOOSE. :-( I did some ghetto tightening with some tape temporarily to make sure the connection is tight.

So it has been bad relay, bad clutch, bad low pressure sensor, bad low pressure sensor signal connector. OMG, Murphy lives here in my house.

BTW, I got under the car again to check if the drier was frozen and I found a lot of oil under the oil radiator, and a bunch of other places. I think the rear main seal is bad too, but that's not an issue for this thread.

I'll post any more findings.

 

>OMG, Murphy lives here in my house.
I hate that guy, one of these days I will find the SOB in the graveyard and Murphy him, even if he's already Murphied[8D].


JPN

 

In my house I am so plauged I changed the Name it isn't Murphy's law anymore it is Johnson's law!!! (My last name)

 

I drove the car for about ten minutes and suddenly there a/c compressor would not engage whatever I did. So I pulled over and got under the car. After a while the compressor engaged and it was making a bearing noise, not really nice. Sounded like marbles.

Does this compressor have an auto-off mechanism that saves it from catastrophic failure? Maybe it is really screwed up and it is shutting off automatically.

 

No shut off for that.
Only high pressure,low pressure,and overheating if it has the sensor.

 

Howcan I check if the overheating sensor is being triggered?

 

I would bypass it. That is the sensor on the back of the compressor.

 

Don't mean to hijack the therad, but I got a question....

I accidently left my recirculate on while driving and my windows did not fog up...Is there some part of my AC which is broke?

 

Hi Jimmy,

I worked until midnight, as a 747 came back due to being hijacked...just kidding, it came back due to oneof the 4 engines quitting in the air.

Anyway, as to the REC, it may be due to a faulty REC damper motor. The motor seems to be located on upper-left of the blower fan, according to Haynes. Also, there is a ventilation damper motor located far-left of the system, which is probably somewhere close to the center of the dash or driver's side of the center console.

Often, electrical/electronic devices can be fixed by disconnecting & reconnecting the connectors, tapping them, etc...

Otherwise, check to see if there's a code for REC. The socket for the climate control (automatic) is B-1, if your 850 has OBD-I in the engine compartment.

Good luck,


JPN

 

The plastic arm at the recirc motor breaks all the time check it out.

 

Just an update. The last three days the A/C has been working fine according to my wife. However it's not been melting hot outside, we've had some rain and that has kept the temperature low, about 30C max.

Under 40C heat, the aircon just doesn't keep up. It turns on/off/on every 5 secs after 20 mins of operation in max.

Could it be that the system just isn't designed for 40C and it can't keep up when the compressor gets old?

On top of this the lambalight turned on today while I was test driving the car. The engine's working fine, probably some emissions thing. I'll scan it when I get home, I have my own PC based scanner. Now I'm REALLY pissed.

 

Another update. Yesterday it was pretty hot (35C) and I had to pick up some relatives at the airport at 2pm. The A/C did not work correctly and we melted all the way home.

The air blew fine when the car was in motion, but every time we stopped at a stop light the compressor would disengage. When the light was green, and I started the car it would engage again and cold air would come out.

What I noticed when we got home is that the engine cooling fan is not always on. My cousin told me that he had a lot of problems with the A/C in his Mercedes and they were related to the engine cooling fan relay. How does that affect the air conditioning?

I also noticed that there is a pressure sensor that is connected to one of the freon lines in the front of the engine cabin close to the right headlamp assembly. Should the A/C disengage if I unplug that sensor? Yesterday the system was not responding in any way to that event.

 

Hi Axel,

850's A/C is a total failure, I understand. It reminds me of a story about a shop in Japan, where they were having trouble with A/C in a Bimmer or Benz. When they inquired a German engineer, he told them that blowing cold air to you is not good for your health...[8D] After witnessing some German products myself and hearing a horror story from a friend in South Korea who works as IT engineer like you, I lost confidence in German engineering. They do produce fine products, but when it comes to reliability...[8D]

Anyway, the engine cooling fans also draw air through the A/C condenser so that the refrigerant can dissipate heat easier. I don't know how 850's cooling fans should work with A/C, but I once had an Accord and whenever the A/C was on, the cooling fans were running continuously regardless of the engine temp.

I'll have to do a bit more research myself.


JPN

 

My other car´s electrical fan is always on when the A/C is working, regardless of engine temperature.

I´m getting pretty tired of this car, I really feel like selling it but I don´t know what I´ll find with my next used car.

 

The A/C uses the fan to cool the condensor. It the fan isn't working properly then the Freon pressure will get to high and turn the compressor off.
That sensor you asked about is the High pressure sensor.
If you notice there is 3 wires on it.
That is 2 circuits. One is for the compressor and the other is for the cooling fan.
Try to find a used sensor and install it and see if that fixes the problem.

 

But is the fan supposed to be on ALL the time my A/C is on? On my other car it works that way.