HKA codes A/C
 

It's hot! The A/C stopped working while on errands on Thursday. :wow:
I left early in the morning and it was ice cold. Halfway through my errands, it would not turn on. Luckily, it was not too hot yet. Yesterday, I checked for codes. Even used the Foxwell 520 Pro to activate the compressor. No go. I checked all the fuses. Even the big 50 amp one.

Does the circuit go through the pressure switch? :dunno: I need to pull out the Bentley manual to check wiring diagrams. The compressor spins freely. It's not locked up. The previous owner listed A/C work. The compressor does look replaced. Its clean compared to the block. It had an oil pan leak on that corner until a gasket replacement stopped it. I've wanted to swap out the pressure sensor since a new aux fan was installed. It sucks that the entire system has to be evacuated. I'll try to reach the compressor connector to ohm it.

Codes:
1B HKA: Magnetic coupling A/C compressor
15 HKA: Pressure switch

Your clutch is shot

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Or bad wire. Does the same loom handle the clutch and the pressure switch?

Asking experts saves time. It's heavy on the wallet too! :rofl:
Can the clutch be replaced while mounted? If it's too much of a PIA, I might as well replace the whole darn compressor. I'm going to miss 42F A/C for a week or two.

I'll check the switch wiring. I pulled off the connector. The AUX fan went full speed. :wow: The brushless fan can really kick up speed.

It needs a new fan shroud. I'll order it. The clutch, fan, tensioner, and belt are three years old. I'll inspect them. I assume with those parts out of the way, the compressor comes out easily. The pressure switch will also be replaced. I'm taking a trip for my birthday this week. I'll get back to it next weekend. For now, I'll park it in the garage and put the BMW cover over it. I hate a dust collection. :bustingup:

I use a 12v battery from a drill to engage the compressor for testing (or filling freon when the compressor won't turn on when slightly too low).

Make sure it doesn't work before replacing. Look on YouTube for if that model you can swap the clutch in place.

A new pressure switch is on the way. I'll do more troubleshooting when I'm back in Austin. The first thing I did was connect hoses and a can. Pressure with the system off was over 100+ PSI or so. I tried to add bit just incase no luck. I'll pull the wiring connect off and check for power. I want to be sure the clutch is shot before replacing.

Equalized 100 seems a bit high but high ambient i could see that happening.

Code reader will show if pressure switch is not reading. Foxwell will command compressor on regardless of conditions normally preventing like fan not working or pressure low.

That's the easiest way to test. Force compressor on with foxwell or a jumper and see if you get cold on the low pressure line.

I cleared the codes after the picture. The compressor was manually turned on. Only the 1B code came back. I tried all the A/C settings and Foxwell 520 Pro command. No luck. So far, all tests show the clutch is shot. Only an ohm test or power feed at the compressor are left to try.

I was 95% sure that was the case, trust me it's not as big a deal to change everything out. To be fair I've found it is best to change out your dryer agent pouch and at a minimum flush out the condenser or get a new one, as it becomes clogged with crap when you have a compressor failure. (If that's what caused the clutch failure)

It's so hot here that I saw the devil crossing the street saying "shit, shit, shit, shit" with every step...

I may have found out about the condenser the hard way...[emoji51] [emoji1787][emoji1787]

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:rofl::rofl::rofl:

A pressure switch has arrived. I'll take a look at accessing the compressor. If it's going to take time, I might just put it in the garage for more maintenance. I need replaced the valve cover gasket. While it's off, two upper new O2 sensors too. I've thought about doing maintenance on the VANOS system. Either replace it or have it rebuilt. How long do VANOS systems last?

The dryer sock will be replaced. A can of A/C flush will clean the lines and condenser. My big air compressor will flush it and dry it.

Don't forget to put it under vacuum... Don't ask how I know that too... [emoji1787]

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I've only paid twice for A/C work. First time, my '91 Dakota compressor failed a few years after arriving in Austin. Second time, I was traveling through South Dakota heading to the Black Hills and Mt Rushmore. The '08 Nitro compressor couldn't handle driving 80 MPH. I was not driving. A dear friend that passed four years ago taught me A/C repair and work. I've done my own ever since. All of them are ice cold. While visiting my folk this week, I did some A/C work too! Farm life starts early!

Does anyone have the pressure sensor and drier sock torque specs? FCP parts should all arrive by Saturday. I'll refresh the A/C system next week. It was almost a full year since having do to major failed maintenance. I say that's a "+".

Final confirmation. The clutch is toast. A Power Probe IV was used to power the clutch. A new compressor and other parts should arrive tomorrow. :thumbup:

Mostly easy day ahead, unless some screwy bolt issue pops up... [emoji23]

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Normal maintenance seems to turn into fix something else too! I'm surprised the compressor only uses three mounting bolts. I couldn't see the condenser drier sock cap. Do top brackets cover it? I sure don't want to move the radiator to access the cap. Sucks both condenser lines are at the top. Flushing the condenser won't be easy. Flushing the evaporator and lines seems straight forward. I expect a few hours taking my time to get it all refreshed. I have some cleaner handy to degrease the hood, engine bay and frame. Hope to get it done on Wed.

Searching for info, I find '03+ have variable compressors. :(

Using compressed air to flush is not a good idea because it will likely have a fair bit of moisture in it but if you do use it, or already have, then at least replace the desiccant. It's not entirely obvious but there should be a plastic cap with a sticker to pry off on the very top of the condenser tube and then you have access to the actual cap.

Work has not been done yet. I just saw an E53 radiator replacement video. The radiator and condenser should move back far enough to reach the drier cap. The shroud and fan will be taken off for degreasing the lower engine area. I'll put it on vacuum for at least an hour.

Seems PAG46 oil is needed. I use oil to lube o-rings.

Looks like a large bit torx bit removes the cap.

What about diving air? I think also he's in Texas in basically end of summer can pick a hot dry day.

How much oil has anyone drained from a compressor?
A search indicates 110 cc (3.72 fluid ounces) is needed for operation.
Is the system max amount like 6.XX ounces?

After 3 weeks, the BMW A/C is operational. The new pressure switch fixed the fan start up. The fan kicks on a soon as pressure builds. A/C is now instant. No more having to drive down a half mile for it to get cold. Or have a hot engine so the aux fan turns on for cooling. Engine idle noise is now drowned out the by AUX fan running. While working and idle, the AUX fan did ramp up speed.

The drier was easy to replace. Removing the top radiator holding bracket allows access. The cap was taken off. Using a bolt, a pry bar lifted the drier assembly. First though, I had a little struggle removing the C clip. A small set of pliers and small screwdriver work great. Wow, it was really dirty. I had to be creative to clean down the drier tube. No metal flakes were found in the system. The previous owner had A/C work done before purchase. It has a lot of dye in it. A lot of dye came out while replacing the pressure switch. A 24mm socket works great. It was only hand tightened. :D The old compressor was drained of oil. The same amount of PAG46 was added. The new compressor was turned over manually to oil it.

It was under vacuum for 1 hour. The Harbor Freight gauge set showed almost 30Hg. I'm sure it didn't reach that low but it showed no leaks. It was left on gauges for 30 minutes after vacuum. Feeling confident, addition of R134a was started. Pressure reached 70+ PSI with the engine off. It was enough to start the compressor. R134a was added until pressures reached the low range for 80-85F ambient temperature. Low side was reading 45 and high side was 225 PSI. :cool:

Is the compressor OEM? Or a replacement OEM? The drier sure looked OEM. The radiator has a tag of manufacture 2018. :thumbup:

For a 96F degree day, temps reached 38F out the center vent while driving. :bmw: