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Any idea where i can order to make a part?

That's one thing I don't know how to do, checking signals. Do I need oscilloscope or smth like that?
 
Nope, a multimeter should suffice. Just check that the tilt sensor is sending out a return voltage or continuity change when it is tilted. I would check that with it installed in the trunk, under actual working conditions. Likely one of the wires is voltage out to the sensor, and the other is voltage back from it when it's tilted to a certain position or positions.
 
That drawing from post 27 sure does help understand what is happening.
eKretz has the right idea about looking at the tilt switch and the valve it controls. My suspicion is the valve is in the "soft close" position so can never get full pressure to the ram when it needs it.
Is there any chance the switch is mounted backwards or something? That could make it think it is always closed or open....
 
I think there's only one way to mount this switch. That's how I see others mounted it as well, who did the retrofit. Its mounted with the connector facing toward the front of the vehicle. I doubt it should be mounted upside down or with connector toward the back of the vehicle, away from the driver.
I checked continuity between pin 1, 2 and 3 on the tilt switch connector.
Pin 1 has continuity to pin 9 on the module connector. Pin 2 has continuity to pin 14 on the module connector, and pin 3 has continuity to ground.

Now I disconnected the switch to see what happens to voltage. Connected voltmeter to pin 1, then connected to pin 2.
Constant jumping of voltage, between 0.626 and 0.954 volts.
It just keeps changing non stop.
Changes so fast I can't even see the full number, it changes again

Now connected to pin 1 again, and pressed the button to open/close the trunk.
The pump pulsated for 2 seconds and voltage jumped to 2.2-2.3 and keep jumping all over in between 2.2 and 2.3. After about a minute, back to 0.6-0.9.

Pushed the open/close button again.
The pump pulsated for maybe like 7 seconds, and voltage jumped again to 2.2-2.3 volts.

Now connected voltmeter to pin 2.
Voltage showing about 0.6-0.9.

Pushed the trunk button.
Pump pulsated for a couple of seconds, voltage jumped to 2.2-2.3v.
After a minute or two, back to 0.6-0.9.

Pushed the trunk button again, pump pumped/pulated for 7 seconds or so again, with voltage jumping to 2.2-2.3v.

1000036266.jpg
 
With the sensor hanging and connector plugged in, connected voltmeter to pin 1.
Voltage around 180 mV, jumping up and down slightly.
Pressed open trunk button, voltage jumped to about 0.580 volts while pump pulsated, and stayed there for another minute or so.

Then connected probe to pin 2.
Voltage jumping between 190 and 200 mV.
Pressed the trunk button.
Voltage jumped to about 0.6V and stayed there for a bit before dropping down to about 0.2V
 
Disconnect the battery and check out whether any of those terminals are a ground. It's a shame there's no indication of what those wires are exactly on a schematic, for instance. With 3 wires, I wonder that the tilt sensor doesn't send one signal for open and one signal for closed.
 
Disconnected the battery. The ground is pin 3. Pin 1 and pin 2 on the tilt sensor show infinite with the ground connector on the car.
 
Disconnected the battery. The ground is pin 3. Pin 1 and pin 2 on the tilt sensor show infinite with the ground connector on the car.

Interesting. Both show no continuity no matter which way the trunk is moved? Wouldn't have expected that. Perhaps your tilt switch/sensor is no good?
 
We're talking continuity between pins 2, 3 vs ground?
I wouldn't expect there to be continuity.

I also have a friend with the same car, so can ask to replicate the tests. But not sure why you think there would be continuity between pins 2 and 3 with ground?
 
We're talking continuity between pins 2, 3 vs ground?
I wouldn't expect there to be continuity.

I also have a friend with the same car, so can ask to replicate the tests. But not sure why you think there would be continuity between pins 2 and 3 with ground?
Since one of them is a ground, I am assuming that perhaps the other pins complete a circuit to ground through the switch.
 
Found the description of the system finally:)
 

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I see a note in there that all switches complete a circuit to ground, as I was thinking that the tilt switch might, but it doesn't say whether that includes the tilt switch. There's a mention of the tilt switch being a hall effect switch, which is interesting. Normally those need a trigger, so perhaps there's a swinging magnet or even just a steel piece inside the tilt switch that it senses. There's also a note that the tilt sensor/switch can be tested through the vehicle with diagnostic software, but if you don't have it wired into the original harness and ECU that is probably not an option for you. A hall effect sensor in this application should have an output voltage when it's sensing the trigger. So with your 3 wire connection, you should have an always-on power in, a ground, and a power out that varies or switches with the tilting of the trunk.
 
It looks like the "relay valve" might be what is controlling low/high pressure. Also I read E39 has no relay valve? I remember you mentioned E39 earlier, did this parts come off an E39?
Do you have 2 tilt switches like the document mentions? Are they both in the same plastic housing they are calling the tilt sensor?
 
Yes there's a little metal "tablet" inside the sensor, that slides freely if you shake the sensor or move it. I opened it to make sure it wasn't stuck.

Based on my previous measurements, it seems to have all that present. 1 wire is ground, and the other 2 have voltage.

I think I can test it with software, because it's connected via K line, but I don't know for sure which software and how to test it.

As I read through the document, I'm suspecting the valve is not receiving power. Because of that it doesn't close, and because it doesn't close, it can't build sufficient pressure.

Relay valve​

The relay valve controls the hydraulic pressure between the hydraulic pump and hydraulic cylinders. It is powered and thus opened and closed by the boot lid/tailgate module.

The maximum possible hydraulic pressure is built up in the hydraulic cylinders when power is applied to the relay valve (valve closed).

Only a low pressure is built up in the hydraulic cylinders when no power is applied to the relay valve (valve open).

The relay valve is closed over the entire opening range when the boot lid/tailgate is opened. The boot lid/tailgate is opened with the maximum possible hydraulic pressure.


So I my pucture, the white connector circled on top, I understand it goes to the valve? So when I press trunk open button, one wire on that connector should be having 12v or smth to close the valve and build pressure?
 

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It looks like the "relay valve" might be what is controlling low/high pressure. Also I read E39 has no relay valve? I remember you mentioned E39 earlier, did this parts come off an E39?
Do you have 2 tilt switches like the document mentions? Are they both in the same plastic housing they are calling the tilt sensor?

On E39 this hydraulic trunk was only an option on "touring/wagon" vehicles. Mine is a sedan. So I retrofitted the system from E38, and the document I posted is from E38.
I did not read 2 title switches, should only be one tilt switch.
I didn't see your reply at first as we replied at the same time :)
I do have a suspicion that something is wrong with the relay valve, I.e. it doesn't close, because the pressure is so low. So I'm thinking how to test if the valve is working or not.
Then next step would be to determine why it's not working
 
Yes you're right, those switches probably activate based on where the metal tablet is inside the sensor.
It's a very small sensor.
Some pictures for reference. But how to tell if it actually activates?
And to answer your question from post #55, I'm not getting 12v on that connector when I press the unlock button.
 

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And to answer your question from post #55, I'm not getting 12v on that connector when I press the unlock button.
That seems to be your problem. Now to figure out WHY?
The tilt sensor switches may have something to do with it. It looks like the two switches are set to different angles of the trunk lid. They both should be activated from 8º to 50º I would set the lid at 30º or so and check continuity through both switches. Then one is closed when lid is closed and the other is closed when the lid is open. Check them each for continuity in their respective positions. That should let you know what is happening in the two switches.
 
Right on, so pin 3 is ground on the tilt switch and I tested continuity between pin 1 and 3 and 2 and 3.
Continuity is infinite, no matter how I move, tilt or shake the tilt sensor, and irrespective of whether the pump is running or not.
I also tried testing voltage on pins 2 and 3, and I think when I tilt the sensor, the voltage reading changes between 0 and 500mV, but only on pin 1. On pin 2, it doesn't seem to change that much.

So I'm not sure if the tilt sensor is bad, or it's the control module, or maybe I messed up the wiring, which I doubt.

I really want to supply some voltage to the pump valve connector, to see if that will make it work properly.
 








 
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