I've been working my way through coolant fan issues, unfortunately I do not have a scan tools to trigger the fans (anyone know where I can rent one?).

So far:
1. Noticed A/C wasn't working
2. Found low speed fan not working (probably killed A/C)
3. Replaced low speed resistor

Current observations:
1. When I turn on A/C the compressor clutch engages but the low speed fan relay does not trigger
2. I open the relay and triggered it manually and the low speed fan and it works fine
3. I have swapped tried all relays none trigger
4. I have checked all fuses
5. Looking at it with a multimeter I see: power source for relay coil, power source for fan and ground source for fan but no ground for the relay coil (which I believe to be the DME call for fan).

Appreciate any ideas

Also:
1. Does anyone have a wiring diagram for the 2003 with a single fan plug?
2. Any ideas how to trigger the fan through DME without a scanner?
3. What signals might the DME be looking for other than A/C on?
4. Is there a way to check coolant temp on the gauge cluster?

 

Some answers I have found:

1. I was able to track coolant temp using the OBC menu, https://www.northamericanmotoring.co...-obc-menu.html
2. The low speed fan and PS fan are working and cycle on at 106C

I have not yet found a wiring diagram to understand why the A/C button isn't cycling the fan, I expect the is logic related to A/C pressures.

 

Update, found out why the A/C compressor is not cycling. While the A/C clutch is engaging, the rubber between the clutch and the A/C shaft is broke (area in red below).

This made it appear that the clutch would stop and start and I would hear it disengage, but from the top of the engine I could see that the center rubber was not spinning.

A/C shaft is cycling smoothly when turned by hand, I hope that simply 18 years of age plus some extra heat due to the low speed fan not working lead to it giving out.

I would much rather put a new clutch face in place than a full compressor, keeping fingers crossed.

 

OK, To address a few things.....
Scan tool is the single best thing to get for care of your mini, for about 70bucks on Amazon you can get a Bmw/mini specific (autophix makes a great one) scan tool that accesses every individual system and it's controller. Abs,are, battery, trans, ecu 1&2 body cont etc,etc.. it's going to pay for itself the first time you use it, it really should be the first thing you buy to compliment the car and be proactive about it's maintenance. THAT SAID. unplug fan connector , there's 3pins two are stacked and the other is ground, run two jumper wires from the eng fuse box 12volt from batt and touch or clip to the pins ground and the other two one at a time, you will get high and low speed (it's obvious which are which when you hear them) if you don't get stage 1 and 2, then you have an open circuit, do a continuity check of all wiring between circuit points , I have the diagram , I'll attach it, also the stage 1 circuit is shared with power steering fan, if the PS Fan is out, it kills stage 1 eng cooling fan (ridiculous I know ... .) The PS fans are notorious for failure before 05/06, you probably have some DTCs that will lead you to the issue , running guess work is really a waste of time, go to AutoZone or similar and they can scan(generic scan only) they may or may not have a bmw specific reader which is where the DTC will reside, and it's not going to activate the Mil (✓ eng) my first Bmw took was like 40 bucks, it really is the key to helping solve whatever gremlin's you got in there. And while I'm on this soap box (only use Blue coolant NO other color, flush if it's anything else. I rebuilt my Whole coolant system, and I have an 06, which has all the production fixes for many of the 02-04 problems that were reported, you ps fan will not have a cover shroud and it needs one, but stainless screen door screen cover will help, it get pummeled with road debris, and sizes, which kills stage 1 , there are more suggestions but I can't write a repair manual right now

I think this is the diagram you asked for

 

Thank you J.M.Sutherland,

I opened the slow speed relay, this allowed me to manually test the low speed and power steering fan without waiting to order a scanner tool. From this I found the resistor issue, replaced it and still no low speed fan as I believe there is logic looking for the compressor to drop pressure (or the engine to hit 106C)

I could see the A/C clutch cycling with no cold air, found the rubber link between the compressor shaft and the A/C clutch to be broken. Fixed that and all is well.