I hope I am headed in the right direction here..I have an 05s

My a/c went out after some rapid cycling one day. A/c light is lit, but compressor doesn't engage. Compressor can be spun by hand, not seized.

I noticed while troubleshooting that all fuses and relays are working, however with a/c switched on the low speed fan isn't on. My guess is that is because there isn't enough pressure to cause the low speed to come on.

I have ordered a compressor, and while waiting I noticed no familiar whir from my power steering pump fan,

I tested the fan on the bench, and it works, as well as all the fuses and relays (the one behind the passenger fuse box as well)

So, I'm wondering... could there be any connection between the compressor clutch not powering, the no low speed fan, and the power steering fan issue?

Any electrical advice much appreciated!!

Steve in Fresno

 

Sounds like you might be throwing parts and $$ at an issue....
get it looked at....
Try a preasure check before you replaced the compressor?! If i recall correctly, there is a preasure switch that prevents it from enguaging unless there is enough psi....
what is your production date....on the door....the power scource for the ps pump fan/wireing changed jan 2004..... some early 2005 have the older wiring, but were updated by dealers...the lack of ps running is not an issue..possibly..take it off...and aply a 12v power to it...see if it spins....should also feel pretty smooth, except for the slight tug when you spin it and pass poles on the magnets....bearings do usually go bad, get sandy...

 

Just reread...you did test the fan....
I would tackle the ac issue....check the psi..too much/too little, will not trip the switch, so it will not enguage, running the rad fan....

 

If the AC clutch is out, the AC won't engage, thus the low speed fan won't turn on, thus the PS fan won't turn on. Can't say that I've ever actually heard the PS fan.
There's a difference between the AC clutch not engaging, and not being powered. Have you checked the power to the AC clutch circuit? There are a couple of recent threads that explain how to check it.

 

Hi Zippy,

Thanks so much for your reply's... It's really great to have some diagnosis help to get you think in another direction.

My car is a 9/04 build date, so not sure if that is a cut and dry factor on the wiring.

As for having a pressure test, I first called my beloved indy MINI shop, and he told me he doesn't do a/c systems because he lost his shirt on a similar situation. Great I'm thinking, the one guy I trust in town won't touch it.

So, I brought it to Pep boys for a free a/c diagnosis, which went to $50 since they needed to evacuate and refill for a pressure test. It is holding pressure.

I bought the compressor because it was only 230 bucks new, with clutch, o rings, and a new accumulator. My initial hunch was that it was the clutch, and I figured I could either replace it only for half the cost, or lots of stuff for a little more. Having spare parts around that may work is a good thing in my book because my wife has an 06s R52. Of which her bypass valve had an issue which I solved with my own... which was replaced with a Detroit tuned one.

I just thought of something... When I was doing some electrical testing, I unplugged the pressure switch electrical connection below the airbox and I heard the low hum of a fan, and although the rad fan by the air inlet wasn't spinning I thought there was another rad fan that was the low speed one.

I know now there is only one fan run at both speeds... Maybe that small fan sound was the power steering fan coming to life? I'm going to go check that now.

Would a short in the compressor clutch coil explain such an electrical demon?

You are right, I am going to take it to a shop soon if I can't figure this out. I do love to tinker though... "D

Sorry for being long winded,

Steve

 

Hi Eric, I believe I have checked the circuit early in my diagnosis. I even double checked my results against a known working car, my other 06s and I seem to remember them being the same. I will double check that too right now and let you guys know what I find out.

 

Your build date car COULD have either ps fan wiring...it was, as mine, delivered with the pre jan 2005 wiring, where the ps fan power is routd from the rad fan...mine was "updated" by the dealer when i got a new ps fan at the first oilchange when the fan was found jammed....
simplest way to check on the update is to check for a plug that looks like a ps fan plug, by the fan connector above the radiator fan plug. When the dealer does the eiring change, that plug comming off the rad fan is cut/taped off, and that wire rerouted, and it is powered off the fuse in the driverside compartment ....if you have it backup sensor, it will share that fuse, or have its own if not....the fan is pretty darn near silent, like a computer case fan...so not sure if i have heard it.
If the preasure is good, check the info like above...not an ac pro, but some basic stuff is easy to check to try to save a few $$.

 

Ok, I re=checked the circuit and lo and behold there is a difference. All relay socket poles test the same between both cars except when I check continuity between the sockets for 86 and 87. On the working car I get 1.1 and I get about 175 on the non working car.

Is there another way to test the clutch by applying power directly? From sight and feel it looks like the power to it isn't easy to get to unless I drop the compressor.

 

Looks like I have the updated wiring as well, I only see one connector with 3 large wires coming from the rad fan (right by the a/c high pressure port) which is identical to my other 01/06 build dat

 

+1
one less item to worry about.
Putting the car in service mode, as it is called is pretty fast....
The first time it is about a 45 min job, but once you know where are the screws/bolts are, it goes faster....
if you do replace the compressor, imo (it is standard procedure), replace the dryer...it also acts as a filter and moisturr remover.they tend to be pretty cheap...is aone time item....tyen bring it to your ac guy for a vacume/refill.

 

Yep that's what I'm going to do as soon as the compressor comes the only thing I worry about is the possibility of an expansion valve problem and the headaches i've read about involving replacing it.

Is anyone familiar with testing or diagnosing an expansion valve?

A big thanks to everyone for taking the time to help me out. If you were all here the first round would be on me :D

Steve

 

No clue on the expansion valve, but if the compressor wasn't engaging, I'd look there first. Having just done this, I'm a fan of the 'Rudy Method', where you access the compressor from below after removing the lower engine mount and pulling the engine back with a strap. Much faster than service mode, and you remove far fewer parts.

 

Update:

I ordered the Ebay $229 dollar Chinese made compressor and took the clutch/coil off of it and installed it onto the installed compressor. As my diagnosis predicted, the coil was fried. The cool thing was, even with the compressor being a "cheapie' ebay unit, all the numbers/dimensions/names stamped into the clutch and coil plates are identical to the oem mini clutch unit.

My a/c fired up, however I still have issues.. the compressor is probably shot as it doesn't spin as freely as the new unit. I figured it had to do with it being in a pressurized system, but I've since read about rough spots while turning the compressor shaft is a sign of a failing compressor.

So, I'll be putting the clutch back on the new compressor and installing it after an evacuation.

A word of advise to anyone attempting to replace the clutch or coil only. Don't save money with the cheapo snap ring pliers at harbor freight.

I like that store for some stuff, but those pliers would cause tense moments with the most calm, level headed people among us.

I went to O'reilly's and got a $20 pair with various tips to tighten in with an allen key...so much easier for removing snap rings. Oh, and I used the Rudy method, however since I couldn't find my ratchet straps, I used a spring compressor. It fit perfectly between a hole in the frame and the lower engine mount bolt which I re-threaded in after removing the mount.


I'll follow up soon!

 

Update:

A/C fixed! I installed the new compressor with the clutch that came on it, as well as the collecter/drier (what a pain that was...not hard, just lots of bolts to remove just to budge the collector 1/2 inch so it could be unscrewed and pulled out.

Blowing nice and chilly, and no more engine bogging when the a/c comes on!

oh, and as a note, the ebay unit came with shims under the clutch plate, so I didn't need to use the old ones.


Steve

 

I am trying to get an answer about my ac on a 2003 cooper s when i put the gauge on it buries the needle start ac and it will drop about half of the red and then kick back up. the fan dont kick on when i turn on the defrost either it is hot air when you sety still but turns cold when you start driving dowen the road

 

If you have power to the AC and all fuses are good... You might want to take the ac cover off, most likely the diode is what fried... Theres no such thing of a ac shorting out. This happen to me this summer, I thought I had to buy a new compressor but my ac guy hoisted the car up, took the end cover off and the diode was burnt. Snapped it out soldered a flat piece of copper wire and just like that ac worked... A 15 min job and saved me $100's of dollars. He said in 21yrs of just doing ac work he has never seen a shorted out compressor. This diode is a safety switch so the dealers can tell you its fried.