I have been driving the '04 R53 lately while I work on the '88 Dodge Shadow, had to replace the head gasket....and it's not quite warm enough to take the '06 R52 JCW car out yet

While driving the R53, I noticed that the AC does not work, no compressor engagement at all. Here's a list of what I have done so far.
This car has the automatic AC system, not the manual style

Refrigerant rest pressure is 80lbs
I have power to the AC relay and fuse under the hood
I tried putting direct power to the compressor wire at the relay terminal, still nothing
Tried tapping the AC clutch with small hammer to see if it would engage, still nothing
Noticed that the AC clutch is a little wet, I suspect it's the systems oil, which means that the front AC compressor seal is leaking, but I have 80lbs of pressure
The little light in the control head will not light up when pushing the "AUTO" button or the AC button. I know the lights work, I checked them with my scanner
There are no codes in the AC system
I tried to activate the compressor clutch with my scanner, nothing happened

So, as soon as I can get the little Dodge Shadow out of my garage, I will put the MINI in there and go into front end service mode and then check the pressure sensor under the air cleaner assembly, and also get to the AC compressor wire connector and see if I either have power to there and also put power to the connector and see if clutch activates.

I'm open for suggestions to try and diagnose this without going to the dealer. I am retired auto tech, I also did AC work in our shop.
Just for info, I have the Bentley manual here, it's basically useless for diagnosing this problem

Bryan

 

Sounds to me like you may have a defective A/C clutch on the compressor. It's a $50 part and can be repaired without replacing the entire compressor.

 

Yea... that's the first thing I'm going to check once I get the nose off the car to gain access to the compressor electrical connection

I'm going to put power to the compressor directly at the connection once I get it apart

Bryan

 

80lbs? That seems high for the low presure side.

Check me on this but if the pressure is not right the compressor will not come on.

 

That is rest pressure, as stated in my first post. Compressor is not running, 80lbs is both high and low side. When compressor runs, it will bring the low side down to maybe 25-40lbs, and the high side will rise up

I need to get the compressor to engage

Bryan

 

Not many of these still around. Would love to hear more about it at some point. Running the mighty T1 turbo?

 

I think I found why my AC doesn't work anymore.

I put the car in service mode, finally got to the compressor, I pulled the wire connector apart for the clutch, applied 12v to the wire for the clutch, and it engaged. I put a test light into the wire going to the connector, started the car, pushed the button, and the test light did not light up...so that means I was not getting power to the compressor.

I put the electrical connector back together, and mounted it back on the compressor. I now started to remove the air cleaner box to gain access to the pressure switch. They really put that switch in a hard place to get at.

Now for some reason, I wanted to make sure that I was not getting power to the compressor....I started the car again, and pushed the AC button....nothing happened. I tried the AUTO button, nothing happened......I kept trying every button on the head unit....and then one time I pushed the AC button, the AC came on....I had to push the button rather hard...I mean harder than normal. This only worked on the AC button.....the AUTO button still won't do anything.

I also noticed that none of the heater-AC controls light up when the dash lights are on....yet they light up when the head unit is turned on. My '06 dash lights in the head unit light up when I turn on the dash lights.

I'm thinking I have a bad heater-ac head unit.....any thoughts on this or what I posted above? I find it strange that the dash lights don't work until I turn the heater controls on....

I'm putting the car back together now...I have located a used head unit....I hope these don't have to be coded to the car like everything else

Pictures below showing progress

Bryan






Hey, I found the connector

notice that there are no dash lighting in the head unit

 

Did the new unit help?

 

The HVAC head unit is due to arrive on Monday.

I will post what happens when I install it

Bryan

 

Update: 4-28-2020

I now have working AC & heater again......I found a guy in a Facebook group that had a complete head control unit for $10 (also picked up another set of stock '06 tail lights to trade for the Euro lights that have the amber lens on top. He also had a complete JCW airbox which I bought also, (for $75)

Basically what the problem was is that the little push buttons on the circuit board inside the head unit were not making good contact. In a post above I had to push hard on the AC button to make the compressor run. I could not make the AUTO button work at all. So while I was waiting for my parts to arrive, I decided to try some contact electrical cleaner in a spray can and see if I could get the little buttons to work again.....and it worked. Guess I should have tried that first before spending the $10 on another circuit board, but it's OK..I have a spare now in case this one fails completely.

One thing that still baffles me is that none of the HVAC control dash lights work when you turn on the dash lights with the engine off and key out of the ignition. All the other interior dash & instrument lights work, but not the heater control head. If I start the car and then turn the lights on, they will work.

I checked my "06 R52 JCW car and when I turn on the interior instrument lights, everything works including the HVAC lights.......I would be curious to know if any other '04 or earlier cars dash lights work as the same as I posted above with my '04 R53......if yours work the same as mine, I'm not going to worry about it, if they don't, I may not bother with it anyway. When the HVAC control buttons are pushed to turn the system on, everything lights up as it should....I don't drive the car much at night anyway.

And as a note here....that HVAC control head is a pain to remove from the car....I really thought I was going to break something getting the old one out. Then I had to fight the wire harness to get the radio head unit back in.

To anyone reading this, I really would like to know about your dash lights in your HVAC head unit, when do they work and when not. Just for my own piece of mind

Thanks guys.....(if anyone needs a picture if the little control head circuit board and the buttons that I cleaned, let me know. I will take a picture and post it up in this thread)

Bryan

 

Great to hear it was a relatively simple fix and great score on the JCW airbox!

Did you see the contacts on the circuit board before cleaning? I’m not sure if the MINI unit uses silicone pads for the buttons, but I’ve seen others where the some kind of chemical/oil leaches out of the silicone and prevents contact between the circuit board pads. I was just wondering if this was the case with your unit, or if it uses actual micro switches on the board.

 

They are very small micro switches... I will post a picture of the circuit board tomorrow

Bryan

 

little tiny micro push button switches