Been assisting a friend with his '02 R50 troubles. Car has just around 12k mi on it. Any help would be much appreciated. Below are the symptoms:

Manual A/C: works only when it wants to!
1.A/C is cold whenever working.Therefore, low refrigerant load can be ruled out.
2.When it works, it works the entire drive duration, but compressor never rests unlike normal intermittent compressor operation as controlled by thermostat.
3.At times,switch doesn't engage compressor clutch. Green light on snowflake switch either blinks or doesn't light up.
4.Upon compressor inspection, there are times when the opposite of #3 happens: Clutch remains engaged while A/C switch is off = compressor is always on even when A/C not in use while engine is running.
5.No low speed fan. Just hi speed works. Infamous green resistor failure, but never had overheating issues though.

Suspects are either of the ff:
1.Snowflake w/ green light switch
2.A/C blower switch
3.Temperature control/thermostat switch
4.Compressor? (hope not)
Logical? Anyone? Any spot on fixes?

Another problem is that both the Odo & Tach Digital Display screens went blank a coupla months back. Pressing the odo reset does nothing. All other gauges & lights work. No SES nor OBD codes though. Car is babied & runs fine aside from faults above.

This community has been a huge help for my R53 maintenance. Any ideas would be much appreciated & most welcome. Thanks!

 

Bump. Anyone?

 

The fact it works sometimes does not mean it has adequate gas...it only means that it has some....if it is low....it will make some cold air...and then stop, until it has sufficient gas coming from the condenser to re-compress.....so I would do a quick recharge....since this is potentially the ONLY DIY fix, give it a shot...remember....too much is bad...so with the DIY kit with the gauges, give it a shot!! The system can only be trouble shot with the proper charge in it anyway.....so it is a good step 1.
Sounds like a bad ac CLUTCH too maybe....you say it is always engaged....you need to replace the compressor to get a new clutch.....unless you have a local place that does the rebuilds.....but this is kinda rare....just a guess. The expansion valve/orifice could be bad/clogged, but this usually happens if the compressor goes bad...a possibility, and the chunks clogs it....if it get by the dryer..(if this happens or the oil is black, you also replace the condenser if it can't be flushed in 2 tries).
It sounds like a an odd issue, but perhaps since I am only guessing, heck that is all anybody can do, on line, it needs to to trouble shot, and that requires tools, etc....and replacing random parts is expensive...sounds like you need to bring it in...could be a bad pressure switch, but unless you have the tools, and skills to test it....you won't know till it gets replaced...

I hope I don't make it sound hopeless, but the AC is not too user friendly from the user fixing standpoint...while it does have few parts, and its operation is pretty simple, it needs some tools, and gauges to work on...

One good thing to note...since the low speed fan has already failed, this often causes the system to run at abnormally high pressures, which can cause an early failure to the compressor....so I recommend getting it fixed...since it may accelerate wear.....if it has not already caused it to fail...a failed AC with a failed low speed fan is common...see the link?! Fix one, with out fixing the other....and it may happen again!!

 

Great thorough approach! We'll go thru every step you advised & hopefully get this fixed. Thanks a ton, Zippy!
Anyone got any inputs on the blank digital ODO & Tach displays?

 

Usually if something like this happens, the dealer would re-flash the car's program....just to see if something is messed up electronically...then replace the unit. It might be woth checking to see if the plugs on the back are on tight....maybe they got loose, and it just needs a snugging up? Not sure if it could be a problem in the computer, since it could be the computer that generates the #'s for the tach to display.... short of swapping it with a spare to see if it fixes it...I am assuming you have already checked all the fuses....
Please get a second opinion before spending much money...I am by no means an expert, and ideas given on any forum are just a starting point on where to look (We do get lucky some times, especially ruling out the simple stuff!!)!!
IMO if the part in question is more than a few $$ and you don't have the equipment to do the tests, it is often time to get some real help, so unnecessary parts are not getting replaced wasting $$, that will not fix a problem.

 

So far the fuses have all checked out. we'll go thru the connectors. It's understood that on-line diagnostics may not always hit the nail, it's still a very good way of sharing/getting sound advice like what you've just given. Thanks much, Zippy!