Air con blowing warm air, radiator fan not spinning?

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MrPT
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Air con blowing warm air, radiator fan not spinning?

Post by MrPT » Mon May 21, 2018 11:42 pm

All too predictably, the sun is now blazing and my air con is kaput. Vents are blowing warm air, even with “maximum snowflake”.

Initially I thought it just needed a re-gas, but this failed to fix it (or find any leaks). The a/c blew nice and cool immediately after the service, but upon heading out a few days later, things got sweaty again. I have also noticed that the radiator fan isn’t coming on under any condition now, which may be related. I usually keep the climate control on “auto” all year round, so couldn’t say when the a/c stopped working. Probably only in the past 6 months.

This is what I’ve tried, so far:

* Re-gas - improved things only for a short time (haven’t checked a/c pressure in INPA yet)
* Visually inspected compressor - the pulley spins when a/c is enabled and stops when it is turned off, which I assume this means the clutch is working?
* Visually checked for leaks
* Removed and inspected fan connector at fan pack end (not traced green cable back to DME yet)
* Checked for dip in revs when a/c engages - none
* Checked fan rotor spins freely
* Checked a/c light comes on

Is there some kind of failsafe that disables a/c if the fan isn’t working? If so, does it make sense that the clutch engages but the compressor doesn’t load the engine in any way? I’m open to the idea of a fan pack failure, it’s just going to be a hard pill to swallow since I just sold a new, spare fan pack that I’d been unable to shift for years. :cry:
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Air con blowing warm air, radiator fan not spinning?

Post by Ducklakeview » Mon May 21, 2018 11:51 pm

Take the plastic cover over the radiator off. Look at the power connector for the fan, two thick wires and one thin green one. Willing to bet the green one has disintegrated.

Done dozens of them, it's the fan speed sense signal.

Let me know...

Mike

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Air con blowing warm air, radiator fan not spinning?

Post by Z4M-2006 » Tue May 22, 2018 9:49 am

As mike says

Usually the fan pack wiring on the fan itself...

Easy to swap out anyway.

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Air con blowing warm air, radiator fan not spinning?

Post by MrPT » Tue May 22, 2018 11:16 pm

I’ve checked that (see my list). It’s in really good condition.

Will remove the fan pack and take a look at all the bits of the loom I can see. Thanks.
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Air con blowing warm air, radiator fan not spinning?

Post by ph001 » Wed May 23, 2018 4:59 am

If a regas temporarily solved the problem, I can’t help thinking you have lost all the coolant again. They usually add a dye when the refill which shows up under ultraviolet light. Have they / you had a good look around with a uv lamp?
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Air con blowing warm air, radiator fan not spinning?

Post by MrPT » Wed May 23, 2018 10:12 pm

Took the fan pack out completely. It's like new.
ph001 wrote:
Wed May 23, 2018 4:59 am
If a regas temporarily solved the problem, I can’t help thinking you have lost all the coolant again. They usually add a dye when the refill which shows up under ultraviolet light. Have they / you had a good look around with a uv lamp?
That's what I keep coming back too as well, but there was a vacuum test cycle on the machine and that showed no issues. It was Kwik-fit though - wouldn't normally go there but I thought WTH for a £40 air-con recharge! They have an A/C guarantee (and the owner was great, to be fair), so will probably speak to them re. a refund if I don't get anywhere.

I'll get INPA working and see if I can check the pressure or force the fan to come on.
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Air con blowing warm air, radiator fan not spinning?

Post by cj10jeeper » Thu May 24, 2018 8:42 pm

Problem on my daughters 1 series was real simple. Local garage went through all the usual, regassed, replaced sensors and alllmsorts. No difference and never charged her
We went to BMW and inminutes they diagnosed that the main engine cooling fan not functioning which stops the air on working. New fan motor unit and all fixed (for near £500...)
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Air con blowing warm air, radiator fan not spinning?

Post by cocojoe53 » Mon May 28, 2018 7:42 pm

I have the same problem 2003 3.0 with just 17k miles...Just started blowing only warm air...My local repair shop wanted $1200.00 just to look at it...Told me if I got to warm to put the top down!...Now my former repair shop

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Air con blowing warm air, radiator fan not spinning?

Post by cocojoe53 » Mon May 28, 2018 7:43 pm

Geez....2004 3.0....

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Air con blowing warm air, radiator fan not spinning?

Post by charlie8 » Mon May 28, 2018 10:14 pm

How are you sure the fan does not come on under any circumstance - do you mean no cooling engine when hot ? ie running idle, revving, does the needle go past middle with no fan ? Thats how I knew the fan was dead, and it takes a while to heat past middle, these engines are very well designed

I think if compressor fires then there is some pressure, but just looks like you have too little gas to cool well, so a leak. I am not sure no fan means no air con, if compressor turns the DME must think all is good. My money is on the wiring which was my problem

The green wire 'looked' ok on mine, but when i started to scrape the wire to find copper to measure voltage it turned to dust, literally, no cooper at all. So I went back into the loom, cut wire, found copper, separated the fan terminals and then just used 3 croc leads to jump all pins and the exposed open green wire. Then it worked to cool engine

Its worth getting the INPA, just £35, as you can test the fan directly, it allows you to fire in a 15, 50, 90% speed signal. It wont tell you if motor or wire, but does allow you to know the signal is being sent and for you to investigate.
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Air con blowing warm air, radiator fan not spinning?

Post by MrPT » Sun Jun 24, 2018 11:22 am

Finally got round to looking at this. I'm using INPA (not "INPA old", which seems to only provide DME info in German) from the Cable-Shack software bundle. I have then switchable D-CAN cable in "K" mode. I've posted a few screens below in case it's useful for others in the future.

Fan test

1. After selecting "E85 E86 - Z4" from the main menu, go into the "Engine" section and choose mss70 for S54

2. Choose "Actuator activations 1" then "E-fan"
inpa01.PNG
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inpa02.PNG
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3. Select F1-F3 to test the fan. It will be very noticeable without the engine running - 90% will have the neighbours turning their heads!
inpa03.PNG
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Air con test

1. After selecting "E85 E86 - Z4" from the main menu, go into the "Body" section and choose Air conditioning
inpa04.PNG
inpa04.PNG (297.49 KiB) Viewed 400 times
2. Then choose "Read status", which will then allow you to view the diagnostic info in "Analog input", "Control values" and "I/O status"
inpa05.PNG
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inpa06.PNG
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inpa07.PNG
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inpa08.PNG
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inpa09.PNG
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Air con blowing warm air, radiator fan not spinning?

Post by MrPT » Sun Jun 24, 2018 11:26 am

So, with no error codes and all switch gear, sensors and the fan working, the below is my issue, right? Low refrigerant pressure, despite passing a leak test at the garage. :?
inpa07.PNG
inpa07.PNG (234.72 KiB) Viewed 400 times
Any idea what it should be under normal operation? Not 1.2bar, I'm guessing!
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Air con blowing warm air, radiator fan not spinning?

Post by Z4M-2006 » Sun Jun 24, 2018 12:47 pm

Well its either leaked out again or AC pressure sensor faulty

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Air con blowing warm air, radiator fan not spinning?

Post by MrPT » Wed Jun 27, 2018 10:45 pm

A check with a manual gauge on the low pressure valve reads 20psi. Bugger.
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Air con blowing warm air, radiator fan not spinning?

Post by bmwaddict » Thu Jun 28, 2018 12:20 am

It may be the actual schrader valves, we had a car in today which had that issue. Then again it wouldn't hold the gas in if one of them were gone. Worth changing both if you've tried everything else?
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