E30 from Ukraine - "Shadow of Intelligence"

[The_Glory]

Air conditioner compressor sensors

In the post about trying to refill the air conditioner, I wrote that in addition to the burst hose, there were problems with the air conditioner compressor pressure sensor. So, I need to figure it out. Maybe this information is somewhere on the Internet, but I couldn't find it, so I had to figure it out myself. I will describe everything, as always, in as much detail as possible, maybe it will be useful to someone.

I have three sensors - I have already written about them in the relevant section.


Safety air switch (64 53 1 390 070) new for E30, E32, E34 4 pins (black and white connectors)
Safety air switch (64 53 8 390 971) for E30 2 pins (black connector)
Safety air switch (64 53 8 390 536) - for E23 4 pins (black and white connectors)

On my wiring, the connector for the low pressure sensor was cut off, and the connector for the high pressure sensor was an early model, with two flat black contacts, type like this:


All my sensors had different connectors:


I solved this not-so-big problem with a homemade adapter. But looking at the ETM diagrams for different years of production, it became clear that there were some differences in the connection of these sensors.

On the 86 diagram, there were two separate high (black connector) and low (white connector) pressure sensors that were connected to the air conditioner wiring in series, one after the other.


The low pressure sensor opened in the event of a freon leak and a critical pressure drop. The high pressure sensor closed at a pressure of 21.2 bar, and opened when it reached 26.6 bar.

In the 87 scheme, there were two separate high (white connector) and low (black connector) pressure sensors, which were connected to the air conditioner wiring in series, one after the other. The sensors were simply swapped in the scheme, and the color of the connectors. The operating pressure ranges of the sensors remained the same as they were.


I don't really understand why they did this, but it's not critical - it practically didn't change anything, because the connection diagram remained serial. In addition, they added a serial temperature sensor on the compressor. Although, on later diagrams it is no longer there. But now we are not talking about it.

On my old dryer there was a fitting for installing two separate sensors. But on the new dryer the fitting was only for one sensor. That is, there was no place to physically install the second sensor. I had to look at an even later diagram.

On the 90 diagram there were already two high and low pressure sensors, connected serially one after the other, but physically they were located in the same housing, with one black connector. The white connector was removed from the diagram altogether. That is, it was already a double sensor - for both low and high pressure. The high pressure limit was increased to 30 bar.


In fact, nothing has changed in the circuit itself - in any case, both sensors are connected in series one after the other, and for the compressor to work, they must both be closed. Since my wiring had both black and white connectors, I decided to install a new original sensor (64 53 1 390 070) with white and black connectors. This seemed logical. Accordingly, I connected them that way - white to white, black to black. At the same time, the compressor did not start until I disconnected the white connector and installed a jumper in the wiring instead of the sensor. At first, I thought that the sensor was faulty. Although, it is new and original. But then I thought the cuts on the insulation of the white connector wires were suspicious.


I tried to "ring" them with a multimeter, and it turned out that the white and black connectors are not connected in series! Strange. The situation became clear thanks to a friend who also installs air conditioning. He bought an analogue of the sensor, on which its parameters were marked:


HP 32 OFF - high pressure 32 bar is off

MP 17 ON - medium pressure 17 bar is on

LP 2 OFF - low pressure 2 bar is off

Judging by this, the low pressure sensor closes at a pressure of 2 bar, and the high pressure sensor opens at a pressure of 32 bar. And they both work only through the black connector. And the white connector closes at a pressure of 17 bar. This was confirmed by practical testing.
That is, these two connectors should not be in series, which is why in my case a jumper for the white connector on the wiring was needed. And the white connector of the sensor is not used in this case.
But I wonder why that white connector is used then? This sensor (64 53 1 390 070) according to ETK is suitable for E30, E32, E34.

Therefore, the answer to this question was found in the ETM 95 scheme for the E34. It shows a similar sensor (B9508), dual for low and high pressure (B8y) with a black connector (X127). The low pressure sensor opened when the pressure dropped below 1.5 bar and closed at a pressure of 2.6 bar. The high pressure sensor closed at a pressure of 21 bar and opened when it reached 30 bar.


It seems that everything is the same as in the 90 scheme for the E30. But, having scrolled through the following diagram, we find on it the same pressure sensor (B9508), but with another built-in separate sensor (B9y) with a white connector (X126).


But there is probably also an error in the diagram. In practice, this sensor closed at a pressure of 18 bar, turning on the air conditioner fan at maximum speed. After cooling, the pressure dropped to 15 bar and the sensor opens, turning off the fan. That is, this is additional system protection through a third sensor, the use of which in the E30 is not provided for by the diagram.

Now everything is clear. So, having this sensor, I decided to use its additional protective function for the E30 as well. This is not at all difficult to implement - you only need to add two short wires, of the appropriate colors, from the temperature sensor for the maximum fan speed on the radiator to the pressure sensor on the dehumidifier. This is drawn in red on the diagram.


In my case, the temperature sensor is also double, but the circuit is similar.


By the way, the diagrams show in blue the connection of the button for manually turning on the maximum fan speed via the standard relay, and the additional lamp on the OVERHEAT control panel. I have already written about this before.

In order not to cut anything in the wiring, I decided to make another adapter - for the temperature sensor with a parallel white connector for the pressure sensor.
I also made a jumper with the yellow connectors so that they would no longer be confused with the white ones. Because somehow German engineers got a little too clever with these connectors, changing their functionality, but leaving the same colors! ) It's confusing.


So, we connect the adapter to the temperature sensor on the radiator. We connect the air conditioner wiring to its corresponding connector. And we connect the white connector of the pressure sensor to the white connector of the adapter. We connect the black connector of the pressure sensor to the air conditioner wiring, as before, through the adapter. And we install a jumper on the second connector of the air conditioner wiring (now it is yellow, instead of white).




A double, or rather triple, pressure sensor.

It's probably not for nothing that there were slots in the wire insulation - it seems that the previous electrician decided to implement the jumper in the simplest way - by twisting directly on the sensor.
But we're not looking for easy ways! )) The slots are insulated, the adapter is connected. Now it is important not to confuse the white connector of the high beam headlight ))


A third pressure sensor is connected to the adapter.


Thanks to this, if the pressure increases to 17 bar, it will immediately be automatically lowered by the fan, and not grow further, up to the critical 30 bar, and the compressor will turn off. I don’t know why this option was not used in the E30, although this sensor was used there.

A dual low and high pressure sensor is connected via a black connector with an adapter for early-type foam.


A jumper is installed on the second connector of the air conditioner wiring to close the wires in a serial circuit. A yellow connector is installed so as not to be confused with the white ones.


This completes the work with the electrical part and compressor sensors. I hope...

But that's all I managed to do. It never got to the point of replacing the hose, again, for the same reason as last time. But now on a more serious scale. After the new roof on the garage, I had to make a new roof on the house...


Therefore, there is no time, no finances, no energy for cars again... it's all over...

By the way, my E53 will now also have to spend a lot of time and finances - it also got ((


It's good that at least the E30 is in the garage, so it didn't suffer.


But, unfortunately, work on it is again postponed for an unspecified period, so there will probably be no news in the near future...

[The_Glory]

My mistake

There is still news, although it would be better if there were none...

I never let anyone drive my car before. And that day, I was "convinced" by a demon! I let a man drive 300 meters down my street and back. But unexpectedly, this trip turned into a real "action thriller"! I can neither understand nor explain the man's further actions... I will not describe all the details, but when he saw a police car passing by, he for some reason decided that he needed to run away from it! Not knowing the area, a "brilliant" route was chosen - to a dead end street leading to a forest and a ravine. Then everything was almost like in a movie - police, flashing lights, sirens, a chase down an alley where the asphalt ends. I would not have gone any further. Especially in someone else's car.

But no - further along the "imaginary road", construction debris,


between concrete pillars


Knocked down concrete blocks in the grass (fortunately not by the engine pallet)


Exit to the clearing with high-voltage poles along such "on the road"




A small springboard in front of a metal support


And then a "drift" sideways on the grass between the pine trees, across the entire clearing.


And a stop somewhere here on the slope, in front of the river below. It's good that at least there was no attempt to jump over it...


Next, the police capture, handcuffs and an abandoned car in the forest. Nearby is an improvised playground for young extreme cyclists.


While I was frantically looking for the abandoned car somewhere, the young extreme cyclists showed no small amount of curiosity about it - they opened all the doors, the trunk, the hood, and climbed around. Thanks to the caring people who happened to be nearby, the young vandals were chased away from the car, and fortunately for me, they didn't have time to ride their BMXs on the hood or roof of my BMW for a "funny video" on TikTok, or just to have fun. The car returned home on its own. Considering all of the above, we can say that I was very "lucky". Only the front apron and the right plastic sill were damaged.
These must be traces from that concrete block.














There is also a crack in the lower plastic protective shield and a miraculously surviving power steering pump bracket, which I lowered lower than it was at the factory. The pan, steering rack also seem to be without damage. But it will be necessary to carefully inspect everything on a lift or inspection pit.
Well, it's good that it ended like this. After all, in the worst case, the car could be "wound" on a pole or a pine tree, or vandalized, or broken into by young extreme cyclists.

The moral of this story is that you shouldn't let anyone drive your car.
I, as a fool, did it the first time, and the last time.

[Northern]

That's terrible! looking at the pictures of where it drove, I expected much worse. Have you been underneath the car yet?

[The_Glory]

That's terrible! looking at the pictures of where it drove, I expected much worse. Have you been underneath the car yet?

I also imagined a much more terrible picture, knowing what kind of "road" it was. But, by some miracle, the engine pan, steering rack, and radiator remained undamaged. At least nothing leaked. I haven't looked at it on the lift yet, I'll have to go to the service to inspect it.

[The_Glory]

The Scale of the Tragedy

So, the day before yesterday, I crawled under the car and discovered some more "surprises"—which comes as no surprise... (

Naturally, the BBS front valance is cracked on the left side and completely scuffed underneath—it definitely needs repainting.








But credit where credit is due to the genuine BBS part—I think a fiberglass replica would have simply shattered into pieces!

My power steering pulley and hose flange sit lower than the factory spec. Miraculously, they survived intact, although the plastic protective shield cracked at the point of impact.


The plastic shield is heavily scuffed, and right behind it, you can see scratches on the engine oil pan too! Again, it’s a miracle the pan didn't crack. It has scratches and traces of... ...of concrete.


Grass under the drain plug.


Front subframe and steering rack—these also show traces and remnants of concrete, not soil.


The same applies to the left control arm bushing.


And on the exhaust system pipes.


Exhaust system mounting bracket (connecting to the transmission) bent from impact with concrete.


White impact marks from the concrete on the transmission housing and drain plug.


No cracks are visible on the transmission housing, though judging by appearances, there easily could have been some...


Scraped paint and protective sealant. At the rear of the underbody.




Scraped underside of the BBS plastic side skirt and a torn-off mounting bracket.


Fuel tank is undamaged; only one mounting point for its protective plastic shield is torn off.
The rear suspension and the rear section of the underbody beneath the trunk appear undamaged.
Fluid levels are normal, the car drives straight, and there are no strange noises—at least that’s a small consolation...

So, these are the results of my stupidity.
A lesson learned for a fool like me, and now I’ll have something to keep me busy during those long winter evenings...

[The_Glory]

Coin Holder

As often happens—out of boredom, while browsing a local online marketplace—I stumbled upon another "treasure" I’d been wanting to buy for a long time. A reasonable price, perfect condition, and the right color (black)—naturally, I had to get it!
So, I finally have an original coin holder!


Part No. 9 – SCHWARZ coin holder (51 41 8 110 033) in black. They also come in other interior colors—though not every single shade, just the main ones: gray, blue, brown, beige, and red.

In my case, it’s black.


Perfect condition.


Mounting bracket with adjustable positioning for various BMW models (E24, E28, E30, E34).
Extreme positions.




Position for E30.

Typically, the coin holder is installed on the driver's door—which makes sense. However, I already have the factory cassette holder installed there.


So, I just test-fitted it. The coin holder simply clips onto the edge of the plastic pocket on the door panel.


Open.


I suppose I’ll be using the cassette holder more often than the coin holder anyway ;) Especially since, with the current inflation, those coins will likely go out of circulation soon... So, just as I originally planned, I’ll install the coin holder on the passenger door instead of a second cassette holder.


Like this.







Door closed.




With coins.




So, that's one more genuine option added to the car's configuration.

[The_Glory]

A/C Re-gassing (Attempt No. 2.5)

So, I’m returning to the A/C re-gassing task.
As a reminder, the previous attempt failed: the compressor hose cracked, and the clutch sensor wasn't working correctly. I’ve already resolved the sensor issue—I wrote about that earlier—so all sensors are now connected properly. Now, I just need to fix the hose problem.
The hose cracked right where it was positioned closest to the engine's exhaust manifold. The high heat caused the rubber to harden, making it feel more like plastic.


On top of that, the hose had been rubbing against the edge of the chassis rail, causing damage in that spot as well.


Fortunately, I like to keep spares on hand, and I happen to have another hose just like it.


Judging by its part number, it’s from a facelift E30 model—it has a shorter metal section and, consequently, a longer rubber section with added thermal insulation. Thanks to this design, it can be bent to route well away from the exhaust manifold, and it features additional heat protection. It seems this was how the German engineers corrected their earlier mistake.

However, colleagues advised me to get a new hose—or rather, to have the old one refurbished. There is a fairly well-known local shop that specializes in this. They refurbish high-pressure hoses by reusing the old metal fittings and crimping new rubber hose sections onto them. But they warn upfront that they offer no guarantee regarding leak-tightness! Not exactly a reassuring service... Still, the reviews were positive, so I decided to give it a try. I sent them my old hose, expecting to get back an identical, refurbished unit. Instead, this is what I received:


The hose ended up longer than the original; consequently, the larger bend radius means it might press against the exhaust manifold. The hose diameter is smaller than before. The fittings aren't angled correctly. And most importantly—the hose isn't crimped into the original fittings but is instead secured with clamps onto modified fittings.


Visually, it doesn't look like a very reliable setup for a high-pressure hose. This isn't what I expected.
I don't know—maybe I'm worrying unnecessarily and the other solution was perfectly fine and functional—but I decided to install my spare OEM hose instead. I also wrapped it in aluminum heat insulation.


Fortunately, I didn't have to completely disassemble the front end; access to the hose mounting point was quite manageable with the right-side grille and headlight removed.


However, to route the hose properly, I had to disconnect another hose from the receiver-drier. Naturally, I installed new O-rings when putting the hoses back in place.


Now the hose has a sharper bend, runs much further away from the exhaust manifold, and doesn't touch the frame rail rib at all. While I was at it, I also slightly rotated the inlet hose at the fitting to position it as far from the exhaust manifold as possible.


Now I can try recharging the A/C again. Attempt No. 2.

This time, everything went smoothly without any issues. 11.9 degrees!


But that was in the morning, while it wasn't too hot outside yet. And then—we ran out of Freon! What a bummer! )) Naturally, there was no R12 in stock, so the technician went to get some and promised to finish the job in the evening.
Once evening came, I arrived for "Attempt No. 2.5"! )) It was already very hot outside, so after the recharge, the A/C was blowing air at around 14–15 degrees. But on the onboard computer display, I saw figures I had never seen there before! )


It seems that the A/C fan—despite all the factory shrouds and air guides being in place—blows hot air directly onto the outside temperature sensor! The BBS valance doesn't have a designated spot for mounting this sensor externally, so I had installed it between the metal valance and the BBS valance. It was fine before, but now, with the A/C fan running, it’s trapped in there like it's inside a thermos! )) I’ll need to relocate it to the brake cooling duct.
By the way, the "OVERHEAT" light on the control unit now comes on when the A/C fan runs at high speed.


So, the A/C is charged and working! It’s a win! ))
On the drive home, it felt quite unusual to be driving an E30 in the heat with the windows up and the cabin cool! )) Awesome!

All that’s left is to button everything up under the hood and neatly route the wiring. I also decided to replace the pump seals in the washer fluid reservoir, as the old ones seemed to be leaking a bit.




Everything is installed and connected.


The compressor hoses are routed as far away as possible from the exhaust manifold and protected with thermal insulation.




And finally, the "finishing touch"! The A/C button with icons.


The icons on my original button were badly worn, so I removed them completely. It looked like this.


I replaced the button—and the look improved significantly right away!

A/C


Recirculation


Full illumination.


Looks great! )

Even though summer is over, I still managed to drive the E30 with the A/C on during a few hot days in September! It's awesome! )


It looks so small next to the Prius )


But the weather took a turn for the worse and the rains started, so I guess the "2026 season" is officially over. I drove a grand total of 137 kilometers this year! ))


Washed, dried, and covered with a tarp in the garage.

My helper probably isn't happy about this—he’s turned away in a huff! ))

P.S.
I’m about to start cleaning up the aftermath of the recent "action."

P.P.S.
The weather has suddenly turned great again, so I might go for a few more rides ;)

[anilatasy]

I haven't been able to check in on this thread for a long time due to a busy schedule. When I finally did and started reading, I was delighted to see the great outcomes at first. Then, I was saddened to see what happened to the X5 E53 and the roof. However, what the E30 went through really upset me; I felt as though it had happened to my own car. Seeing the terrain the car had traversed, I had expected a much worse outcome, but thank God, the undercarriage isn't in such bad shape.

I am sorry about what you went through, but please don't blame yourself. Sometimes, one's judgment simply fails. I suppose this was an experience you were meant to go through. The damage is all fixable, and I can't wait to read about the repairs you'll be doing.

As I’ve wished before, I hope everything turns out exactly as you hope.

Wishing you many enjoyable winter days in your garage.