[Aferanova]

2012 X3 with N55-
So I’ve notice intermittently when I start driving, the ac won’t get cold, even driving for ~30 mins if at low speed / city streets. I’ve pulled over and confirmed the no AC at these times is because the electric radiator fan is off.

Now what’s interesting, is if I speed up to around 50mph, the electric fan kicks in and runs fine even once I slow back down. It’s an almost instant change once I hit that speed I start getting ac.

Also if I let the car sit and cool down, often the fan will then work from the start.

No overheating issues have been noticed. I assume the fan itself and fuse are fine since it can turn on. Anyone have ideas? Could it just be a failing relay? How can I test?

[Wgosma]

Do you have a code reading device?....checking for any fault codes a good place to start when diagnosing a problem.

The fan's operation/speed is variable and controlled by the engine control unit (ECU), which is also receiving an input for coolant temperature from a sensor on the outlet (cold) side of the radiator, read here https://www.newtis.info/tisv2/a/en/f...ic-fan/XZ4xFVp. Looks like coolant temp and a/c system pressure info are feed to ECU so the car's brain is looking at this info and modulating the fans operation based on those parameters.

My GUESS is your a/c system is low on freon, that can cause symptoms such as you're experiencing, but that's just a guess. Fault codes is good place to start - so you need a code reader (such as phone app BimmerLink) or have a shop diagnose.

Good luck/Bill

[Aferanova]

Originally Posted by Wgosma

Do you have a code reading device?....checking for any fault codes a good place to start when diagnosing a problem.

The fan's operation/speed is variable and controlled by the engine control unit (ECU), which is also receiving an input for coolant temperature from a sensor on the outlet (cold) side of the radiator, read here https://www.newtis.info/tisv2/a/en/f...ic-fan/XZ4xFVp. Looks like coolant temp and a/c system pressure info are feed to ECU so the car's brain is looking at this info and modulating the fans operation based on those parameters.

My GUESS is your a/c system is low on freon, that can cause symptoms such as you're experiencing, but that's just a guess. Fault codes is good place to start - so you need a code reader (such as phone app BimmerLink) or have a shop diagnose.

Good luck/Bill

Thanks Bill! I do have a code reader and can plug it in tomorrow and check. I’m assuming if it’s freon there won’t be any faults.

So if low freon you’re thinking the ac system gets up to proper pressure when speeding up causing the fan to kick on? I had freon Evacuated and re-filled last summer.

[Wgosma]

If you had the a/c evacuated/filled just a year ago then I think low freon is not the cause - I only know that low freon can cause intermittiment a/c operation.

So something else is going on, it's a bit beyond me. One thought is the ECU looks at coolant temp a the primary parameter....if it goes 'high' then fan speed is increased to reduce engine temperature; excess engine temp. is critical and must be lowered or you're into overheat, potential major damage.

The ECU looking at the a/c system pressure has perhaps a separate / secondary effect on the fan operation. These a/c systems are variable volume (well, mine is in my 2012 X3 w/M-52 motor), so they are always 'engaged', so to speak - there is no kick 'on/off', the compressor is always operational, only the volume of the compression chamber is varied on this type of compressor.

So it may be that the ECU a/c pressure monitoring is secondary component involved in monitoring the engine temperature and cooling system (fan) operation to insure proper heat transfer for the a/c system. My older BMW sedans had 2 fans, a main and aux fan - the aux fan was specifically there for the a/c circuit and ALWAYS turned on whenever a/c was engaged - that fan assisted/insured proper air flow for the a/c system components. These newer cars only have one fan, so that fan has to be capable of handling the max heat transfer load of engine in operation and a/c engaged/operational. So maybe this monitoring of the a/c system pressure (and feeding info to the fan speed) is related/proportional to the heat transfer performance of the a/c cooling circuit - and if the pressure goes 'out of range' the ECU takes note and increases (or decreases/shuts off?) the main fan?

Well, it's a bit beyond me how this system operates....

Check for any codes then go from there.

Bill

[Marty in NY]

Originally Posted by jvirgi

Thanks Bill! I do have a code reader and can plug it in tomorrow and check. I’m assuming if it’s freon there won’t be any faults.

So if low freon you’re thinking the ac system gets up to proper pressure when speeding up causing the fan to kick on? I had freon Evacuated and re-filled last summer.

Why did you evac the system last summer? Was their an issue? Any symptoms like the one you're writing about now? Have you tried a cold start and then driving a while with the a/c turned off the whole time, let your oil gauge get to operating temp, then drive a bit harder and see what happens with the fan?

[Aferanova]

Originally Posted by Marty in NY

Why did you evac the system last summer? Was their an issue? Any symptoms like the one you're writing about now? Have you tried a cold start and then driving a while with the a/c turned off the whole time, let your oil gauge get to operating temp, then drive a bit harder and see what happens with the fan?

Last summer the ac just never got real cold. And the place I took it to didn’t see anything else wrong so just evacuated and refilled freon to make sure the right amount was in the system and it worked well.

This feels different because it blows nice and cold once the radiator fan turns on.

I can try running it with ac off and see what happens, what are you thinking?

[Marty in NY]

Originally Posted by jvirgi

Last summer the ac just never got real cold. And the place I took it to didn’t see anything else wrong so just evacuated and refilled freon to make sure the right amount was in the system and it worked well.

This feels different because it blows nice and cold once the radiator fan turns on.

I can try running it with ac off and see what happens, what are you thinking?

I was thinking two things:
1. Is your a/c issue and the fan observation related or not? By driving at temp and then a bit harder with the a/c off, I would hope to isolate the two to see if you're having just one issue, two issues or if they are related. Just troubleshooting diagnostics.

2. If you needed the a/c evac/filled last year, then I wonder if you have a small leak somewhere. I have never needed to have that done on any car I've owned and I tend to keep my cars a while, my current X3 is 9+ years old, a/c works well.

[e30lover318i]

You need to have the vehicle scanned. Your hvac and dme will tell you if it’s having fan activation issues. I just did an e60 fan last week with intermittent activation issues, I assume If that gives code a newer chassis would as well. Easy way to check fan is to start vehicle and turn AC on if the fan does not come on with in 60 seconds id say the fan is no good, normally it’s the fan module that fails

[Aferanova]

Originally Posted by Wgosma

Check for any codes then go from there.

Just Scanned the car and have 0 error codes.

Originally Posted by Marty in NY

let your oil gauge get to operating temp, then drive a bit harder and see what happens with the fan?

I'll try later today
I'm not positive if there was an actual freon leak last year... a few years ago i had ac issues and i messed with adding / removing freon, to later find out it was actually an old battery that was just conserving power and not running the ac. So then when i later had ac issues and freon needed reset, i'm assuming it was my fault for messing with the proper amount.

Originally Posted by e30lover318i

You need to have the vehicle scanned. Your hvac and dme will tell you if it’s having fan activation issues. I just did an e60 fan last week with intermittent activation issues, I assume If that gives code a newer chassis would as well. Easy way to check fan is to start vehicle and turn AC on if the fan does not come on with in 60 seconds id say the fan is no good, normally it’s the fan module that fails

Its somewhat intermittent, this morning on a cold start, the fan immediately comes on and off as i hit the ac button on the car. When its on the fan will cycle from low to high speed every 15 seconds or so.

If i had to say theres any trend, i'd have to say the times it doesnt work from the start are more likely hot days.

[Aferanova]

I wonder if i can test the cutoff relay with a multimeter and see if its passing a pulsing voltage?

[Wgosma]

Originally Posted by e30lover318i

You need to have the vehicle scanned. Your hvac and dme will tell you if it's having fan activation issues. I just did an e60 fan last week with intermittent activation issues, I assume If that gives code a newer chassis would as well. Easy way to check fan is to start vehicle and turn AC on if the fan does not come on with in 60 seconds id say the fan is no good, normally it's the fan module that fails

that makes some sense, i bet if a/c is engaged the fan should fire up, run continuously, tho speed may vary depending on load....sort of similar operation to the older cars with 2 fans, the aux fan was always running with a/c engaged, but then again one never knows how these Germans have designied/changed these systems as the car technology has evolved over time.

I just fired up my X3, with a/c set to 72F.....fan sat still, turned a/c down to 64F and fan came on, back up to 72F and fan stopped. it's 55F ambient temp here in Nevada this morning, hmm.....

[Marty in NY]

Originally Posted by jvirgi

I wonder if i can test the cutoff relay with a multimeter and see if its passing a pulsing voltage?

You may find this of interest in case you didn't already dig it up yourself.

https://www.newtis.info/tisv2/a/en/f...ic-fan/XZ4xFVp

Are you having any of these symptoms? Of course this is if you have a complete failure which it doesn't sound like you are having - -yet

Diagnosis instructions

Failure of the component (the fan)

If the electric fan fails, the following behaviour is to be expected:
Fault entry in the engine control unit
Power reduction (if engine overheated)
Check Control message in the instrument panel
Damage to thermally critical components in the car front end after stopping the engine (post-heating of the engine)

Click the link to read the entire page. I don't think your multimeter is going to do what you want as its a pulse width modulated signal. You would need a scope but would also need to know what a good signal looks like.

.

[Aferanova]

Originally Posted by Marty in NY

You may find this of interest in case you didn't already dig it up yourself.

Diagnosis instructions

Failure of the component (the fan)

If the electric fan fails, the following behaviour is to be expected:
Fault entry in the engine control unit
Power reduction (if engine overheated)
Check Control message in the instrument panel
Damage to thermally critical components in the car front end after stopping the engine (post-heating of the engine)

Thanks, yea i had a read there, i'm guessing its not the fan itself since when its not running, i dont get any of those issues.

I'm thinking its either a

• failing relay
• intermittent failing compressor
• low freon charge

i'm not real convinced on these... Here's a new theory i thought of when responding to the freon charge question :

A dying battery? Maybe during prolonged times not being driven during covid, its drained the battery and now maybe if the car has sat too long it will keep the ac compressor off and when i speed up the battery then gets enough charge to turn the compressor back on and it continues to work. That would explain why it works this morning (12hr after last driving).

I'll plan to let the car sit for at least 24hr before driving and see.

Curious if theres an easy place to hookup a multimeter on the compressor to make see if its getting power if the next time i find the fan not running.

[Wgosma]

You can use the On Board Computer (OBC) to take a look at the car's system voltage in real time - use the 'hidden menu' and you can get a continuous readout of voltage as you drive.... give you an idea of battery/charging system status.

[Marty in NY]

Originally Posted by jvirgi

Thanks, yea i had a read there, i'm guessing its not the fan itself since when its not running, i dont get any of those issues.

I'm thinking its either a

• failing relay
• intermittent failing compressor
• low freon charge

i'm not real convinced on these... Here's a new theory i thought of when responding to the freon charge question :

A dying battery? Maybe during prolonged times not being driven during covid, its drained the battery and now maybe if the car has sat too long it will keep the ac compressor off and when i speed up the battery then gets enough charge to turn the compressor back on and it continues to work. That would explain why it works this morning (12hr after last driving).

I'll plan to let the car sit for at least 24hr before driving and see.

Curious if theres an easy place to hookup a multimeter on the compressor to make see if its getting power if the next time i find the fan not running.

Not sure about that, my car sat for two years while I lived elsewhere and when I got back everything, including the a/c worked just fine. Mine too has sat due to the virus for the past 6 months but I fired it up and drove it the other day and the a/c worked fine right off the bat. I always have kept it on a battery tender though.

[e30lover318i]

Find someone with access to a multi directional scanner to activate the fan. If you have no codes in your hvac or DME I’d find that odd, your hvac should also be able to show codes for low pressure and high pressure sensors. If you have no hvac codes for ac pressure related issues your chasing your tail, It’s very difficult to diag intermittent issues so my suggestion is start by replacing the fan assembly since the module is integrated with the fan that’s open to the elements and extreme heat variations.

[Aferanova]

Did some troubleshooting and looking for your ideas.

- Issue is time dependent. Once driving the car and getting the AC working after getting up to speed (>45mph), the AC continues to work just fine for around 18 hours. After that, upon start it no longer works until i get it above 45mph. It literally doesnt matter how long its driven... as soon as it gets above a speed in that range, its works within seconds.

Then I Installed ISTA + to read all fault codes beyond my cheap scanner.
- See attached image for faults that appear to be relevant. Battery is showing in there, though i dont see any undervoltages current anywhere, or any faults showing AC components turned off for undervoltage.
- AC compressor shutdown fault is not current code. The details say it shuts down if it reads under 2 bar but mine is currently above that.

Some readings:
With nonworking AC before driving / working after driving
- Refrigerant pressure: 8bar / 13 bar
- AC Compressor: 'switched on' / 'switched on'
- Electric Fan Signal: 7.03% (meaning its told to be off) / 28.13% (Fan on)
- Battery Voltage (multimeter): 12.3V (PRIOR to starting) / ~14.8-15V with car on
- Battery Voltage (ISTA - car on): 14.32V / 14.79V

So What do you think? I think this mean the Fan is fine... the computer is telling it not to be on. So its either the Freon Pressure (maybe it is indeed too low)? Or the battery has issues.

I read on another site the high side Refrigerant pressure should be between 160-200psi (11-14 bar), So my guess is that my highside pressure at 110psi (8 bar) might be too low to activate the fan.

When i had the freon evacuated and filled last year the stuff they put in supposedly can be seen under UV light, so i'll look around for leaks.

[Wgosma]

I'm putting my money on low freon charge (leak), let us know what you find with the UV lamp -

[e30lover318i]

If you said someone recently re charged the system it’s very possible that caused your code, it also says it not currently present so it’s a history code. Try engaging your fan with your software. If it doesn’t engage that’s telling you it’s an activation issue. And if it’s intermittent you might want to try different times, maybe let sit for 24 hours and try again type situation?

Also see some battery codes, that can cause software to do odd things, is it possible your driving the car enough to charge the battery allowing the fan to engage? The fan pulls a lot of AMP’s

Also speed theory, possible fan could be spinning do to air flow? Dead spot in motor? Example hitting a starter to get a car to start... spinning fan to get it to engage?

[pungo]

Originally Posted by jvirgi

I read on another site the high side Refrigerant pressure should be between 160-200psi (11-14 bar), So my guess is that my highside pressure at 110psi (8 bar) might be too low to activate the fan.

Yeah, 110 is way too low, should be 160-300 depending on ambient temps and humidity. Running low is not good for the compressor.

If you have dye in the system, you might be able to see the leak with a UV light if it's in a visually accessible location. check the service ports valves and hoses where they attach to the compressor since these are common leak locations.

[Aferanova]

Originally Posted by e30lover318i

If you said someone recently re charged the system it’s very possible that caused your code, it also says it not currently present so it’s a history code. Try engaging your fan with your software. If it doesn’t engage that’s telling you it’s an activation issue. And if it’s intermittent you might want to try different times, maybe let sit for 24 hours and try again type situation?

Also see some battery codes, that can cause software to do odd things, is it possible your driving the car enough to charge the battery allowing the fan to engage? The fan pulls a lot of AMP’s

Also speed theory, possible fan could be spinning do to air flow? Dead spot in motor? Example hitting a starter to get a car to start... spinning fan to get it to engage?

So the battery fault is currently showing as a fault. The freon charge last year was because I had messed with it I believe. So now, I checked freon and there were no leaks under UV light.

The fan seems to operate fine because when it’s off, the computer is telling it to be off based on the 7% signal.

I can’t seem to manually activate the fan in ISTA - I’m guessing because I’m using an ENET cable? Any ideas on that?

Root cause I believe is there isn’t enough pressure on the high side after getting compressed. So I thought maybe low battery is affecting how the compressor operates

My thought to test if battery I used jumper cables with another car. Still no luck. Not sure if that was the right way to test. I’m guessing it’s still either faulty battery, or maybe the clutch on the compressor is going bad or something and something about the higher speed gets compressor clutch working??

Ideas??

[Wgosma]

Originally Posted by jvirgi

Root cause I believe is there isn’t enough pressure on the high side after getting compressed. So I thought maybe low battery is affecting how the compressor operates

I’m guessing it’s still either faulty battery, or maybe the clutch on the compressor is going bad or something and something about the higher speed gets compressor clutch working??

Ideas??

My guess is that if low battery/system voltage was the issue you'd be seeing other 'faults' and problems in addition to the a/c issue - these cars can be highly sensitive when a battery/system voltage falls out of range (low).

I'd tend to be suspect of either the system's freon fill or compressor itself - you could have a leak and not been able to spot it with UV lamp. The compressors on most of these modern BMW's are 'variable volume' type, there is no clutch to engage/disengage, they are always compressing - only the compression chamber volume is being 'regulated' based on a/c demand and pressure in the refrigerant system. Read here for details https://macsworldwide.wordpress.com/...pressor%20head.

Maybe time for a visit to Mr. Mechanic.

Good luck/Bill