Official AC Thread

Post by **MadeInJapan** » 07 May 2007, 17:01

Low gas...should be filled with car running. Find the A/C filling thread in the repair database. It will tell you how to jump start your compressor. It needs to be running when you fill it.

Buck380 · Post by **Buck380** » 19 May 2007, 22:43

Was just chatting with a local mechanic about diagnosis of possible chronic leakage from the evaporator on my 850...he said if you've been using dye in the system, it might show up (under black light) at the end of the drain line coming from the evap compartment.
Danged if I know where that drain is...

Post by **MadeInJapan** » 20 May 2007, 05:44

It's very hard to see....it's "up in there" and doubtful you can really see it...some have used small mirrors and the black light that actually directs the beam. I would eliminate other leaks first....but for 850's the evaporator is rather common if you have many miles on the car and the A/C doesn't hold a charge.

Post by **Ozark Lee** » 20 May 2007, 10:33

My Air Conditioner crapped out this week as well. My wife was driving the car at the time and said that it worked fine on the way to the office but wouldn't run on the way home so I feared the worst, that of course being an evaporator failure. To my surprise I hooked up the gauges and I had 105 lbs of pressure in the system without the compressor running. Whew.

I then moved inside the car to investigate why the compressor would not run. I have a manual climate control system and I noticed that the blue Air Conditioner LED would not illuminate if the fan switch was in any position other than off. I further found, by removing the radio, that if I squeezed the Air Conditioner / Recirc. switch I could get the system to work. Ah Ha - a bad switch.

I actually went a step further and repaired the switch. This is a very difficult job and I don't recommend that anyone try it if you are not:

A) very clever and handy and, at the end of the day

B) willing to shell out US $95.43 for a Volvo part number 6802442 at your local stealership.

None the less here is how to fix the switch if you have a manual climate control unit.

First you must remove the knobs on the control unit, the driver side and passengers side temperature control as well as the air direction and fan speed knobs. Behind the drivers side and passengers side temperature control knobs are two Phillips head screws. Remove the Phillips head screws and remove the face plate. The AC / Recirc switch and the fan speed switch may or may not come out with the faceplate. If the switch does not come out simply pull it out of the control head and unplug the connector. At that point move to a well lighted bench or a well lighted dining room table.

Here is the part you are dealing with.

Before I took the switch apart I tried spraying it with a big dose of contact cleaner but it made no difference in its operation.

You next need to disassemble the switch which is accomplished by prying the retainer tabs that are molded into the plastic shell. When you take the switch apart it explodes into a pile of pieces and springs and looks like this.

From here I determined that I had what appeared to be a loose solder joint as well as a dirty switch contact. The suspicious solder joint is here but it does not show up well in the picture.

I re-soldered the joint and then set out to reassemble the switch. This is where it gets tough. The first thing you need to do is try to figure out is how that pile of parts went together in the first place. I figured out early on that the smallest springs and the brass caps made up the detents on the switches. They go together like this.

I then figured out where and how the two plastic pieces fit into the switch assembly, they go in like this.

From here I was really stumped on how to reinstall the switch contacts and springs, I could sorta see how they should go but there is no way to maneuver them into place and then try to put the switch assembly back together. At this point I unsoldered the LEDs and removed the PC board. This is not a necessary step but rather a stumble on my part. The LED's actually snap into their housing and this was the key to success on putting the switch back together. Once the PC board is removed from its shell the next step is to position it into the opposite shell which has the plastic sliders and springs already in position. It will then look like this (I had already reinstalled the LEDs).

The next step is to pre-load the switch contact springs and the switch contacts. I found it easiest to load the springs first and then insert the switch contacts behind them, trying to insert the springs after the contact was positioned was nearly impossible and resulted in much looking around on the floor for the spring that just went flying. Properly done it should look like this.

From here it is a matter of joining the two halves of the switch shell which takes some delicacy as the prongs must be inserted back into the socket at an angle. I tried to preposition the actual switch "knobs" into the shell for this process and found that it would not work. At this point I simply put the shells back together with the thought that I could put the "knobs" back in after the assembly was complete. It did work. Here is a fuzzy picture - my mind was fuzzy at this point - of the switch reassembled.

From here simply insure that the small springs and the brass caps are loaded into the "knobs" and snap them into place from the front. There is an up and down but it is obvious as the brass cap will ride on the molded detent in the shell and the cam at the bottom controls the plastic sliders that maneuver the switch contacts.

From here it is a matter of putting the switch back in the car and reassembling the control head. I was not very confident in the repair so I special ordered the Volvo p/n 6802442 switch as well as a pair of Volvo p/n 3524511 (US $12.10 each

) lamps but the system has worked perfectly since my switch repair and I think I will hold off on installing the new one to see how long the repair holds up.

...Lee

Post by **Maxbaby** » 28 May 2007, 11:41

Thought I'd add this to the A/C thread. I just had my A/C system charged with the Duracool mobile a/c kit. There are a few references to it here and on other posts. One of the things I learned in researching it is that if you are going to use these products you need to have your A/C system purged of whatever is in there first(usually R134). There are a variety of reasons, including that they are of a propane/butane base and are flammable, and mixing them with other things can be bad for your mechanic's equipment if he does not know this. In the end, my A/C guy said it's just not wise to mix them with other gases.

Another really important reason to have your system evacuated is to ensure that whatever air is in the system is purged. Obviously if your system is leaking out the gas (necessitating that yearly or monthly charge), then air will get in. But with air comes moisture, and I gather that only accelerates the need to replace the evaporator or whatever it is that's leaking on your system.

At the moment, my A/C is just fantastic. The mobile kit came with a can of "leak stop" stuff, which supposedly will plug small leaks. No substitute for replacing whatever is leaking, but maybe a good stop-gap to delay that big bill down the road. I'll add a post down the road updating how long it lasts.

Racemaster33 · Post by **Racemaster33** » 10 Jun 2007, 20:40

I've got a 98 S70 Turbo that is doing something strange. The AC will work fine for a while then it will stop coming out the vents, all of them. The AC is still cold and the fan motor is still running fine but all the vents shut off. I've tried it on every setting and fan speed but once it makes this "change" that's how it stays until we shut the car off and let it set for a while. It sounds like either the control unit or some damper control motor is overheating. Has anybody see this problem before? I've seen domestic (chevy) cars & trucks have damper motors go bad and not allow the driver to choose the location they want the air to come out, but never this. If anybody can help please let me know. My car is black and I'm roasting!

mouchra · Post by **mouchra** » 24 Jun 2007, 09:54

tomservo wrote:Well I got the unit today, which I thought was pretty fast, and installed it in like 1 min. and everything works great. A/C is cold, all vents are good. I am so happy. Plus it was relativly cheap. Yeah! Thanks again!

Hello, where in the car is this unit? I have the same problem in my 1998 V70. I will try to change the controlling unit.
Please let me know where yours was at.
thks.

Racemaster33 · Post by **Racemaster33** » 24 Jun 2007, 17:43

You changed the main AC unit or the flap control motor? Where you having the same problems I talked about? Did it fix the problem? Where is it located and where did you get the part. I appreciate any help you can offer.

mouchra · Post by **mouchra** » 24 Jun 2007, 20:07

No, I was replying to "tomservo" who replaced the controlling AC unit and fixed his problem which seamed very similar to mine, where the AC all of a sudden stops getting the air cold and after i stop the car it starts working again. I have not lost any pressure for the R134.

pmpalma · Post by **pmpalma** » 04 Jul 2007, 17:00

So it seems that there's two things that might be causing an eratic A/C operation. Faulty compressor clutch and the thermal switch.

I've read the how to on the clucthc, but seem to find nothing of the thermal switch.

Could someone kindly point out how to short that darn switch and, naturally, where is ity located??

Tx to all