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Old 5th June 2020, 19:03   #41
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Am I right in thinking that it is not very plausible that my battery is the problem? Have I ruled this out enough to say that I should keep looking at the amp-drain from the car's electronics?
No Vinnie, I think the battery could still be a problem.

Measuring the off-load voltage is not a reliable indicator of a battery's state of charge. What happens to the voltage when the starter motor is drawing a huge current is a good indicator.

You have the additional problem of a 0.7 amp current flowing when MGR's data suggests it should be about 5% of that figure.

So, solve the current drain first then evaluate your battery's condition.

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Old 5th June 2020, 23:47   #42
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Just checked the voltage. It now says 12.25v. This after roughly 48 hours.

Just after being charged: 12.45
24 hours later: 12.29
Again after 24 hours: 12.25.
Considering that the battery might give a high reading just after being charged, I rather look at the last 24 hours. Which says it lost 0.04 volts over 24 hours.

I'm not sure what that really says, but if the car won't start with anything lower then 11 volts. I still have 31 days before the battery is at 11 volts.
Off course, this is without any load on it. When I reconnect the leads, it will give a very different picture.

Am I right in thinking that it is not very plausible that my battery is the problem? Have I rulled this out enough to say that I should keep looking at the amp-drain from the car's electronics?
If these are the readings with the battery not joined to the car then your battery needs dumping.---
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Old 6th June 2020, 04:29   #43
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Right, check. Batter = to be replaced.
But first: let's continue with going down the fuses and all. I should have some time this afternoon to dive back into it. I even made a list of things to disconnect. Fingers crossed something good is coming out of this.
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Old 7th June 2020, 07:19   #44
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I didn't get around to check the car out properly. So, instead I spent my time making an overview in Excel with the fuses, some of the relays and possible other things I might had to disconnect. This time I changed my approach slightly to the way I did it a previous time.


My method:
- the car was unlocked when I disconnected the battery 2 days ago
- I checked the voltage, it said 12.24 volts. Just in case, I connected my battery charger and left it for a few hours until it said "battery charged - trickel charge"
- I disconnected the battery charger
- I put a clamp on the bonnet switch
- I put the multimeter in series via the - lead (yes, I listened to you guys)
- I put the multimeter on 10a setting (see a few posts back regarding the hot switching and damaging the meter)
- I waited till the amps would go down (after a few minutes)
- I first tackled the engine bay
- then moved to the interior and worked my way down on my list, noting every number the multimeter would give me (including some notes)
- While in the interior I kept the doors closed and waited for the amps to go down again before doing anything
- I had to disconnect the glovebox the whole time, otherwise I couldn't get to the fuses
- when the amps would go up, I would wait for a few minutes before continueing, if nothing happened I would continue to the next fuse/relay/plug

The goal was to find something that would turn 0.07 into 0.03 (or very close to it).

These are my findings:
https://drive.google.com/file/d/1PZ2...ew?usp=sharing
(PDF file via Google Docs)
or:
https://we.tl/t-pE5B6fbaGF
(Same PDF file, but via WeTransfer)

In short, these are the things that stand out from the other things I wrote down:
- I had 2 moments where the amps would suddenly go up to 0.38, without me doing anything. The first time I was still wondering which relays would be R1, when I saw the amps go up suddenly, and go down after +/- 30 seconds. The second time was while I was inside the car, writing numbers down.
- There where a few times when the amps would be between 0.06 and 0.07 and the meter kept switching between these 2. I wrote down 0.07 as it seemed the safest number to go with for the moment
- when pulling the middle fuse, onderneath the largest master-fuse (50a), the amps dropped to 0.03
- When pulling relay 10 (a small one) the amps would go up to 0.38 for roughly 1 minute. After pulling it a second time, the amps stayed at 0.07 and didn't change. This might have been one of those moments when the amps went up without a clear reason
- pulling fuse 5 in the interior, made the amps go down to 0.03 (I'll get back to this below)
- I have 2 piggy-back fuses, which made no difference when pulling
- when pulling fuse 20, the amps went up to 1.18 and stayed there. Putting the fuse back made the amps drop to 0.38 and eventually to 0.07
- When I put fuse 27 back, it made the amps go up to 0.37, and eventually down to 0.07 again
- pulling the LSM made the amps drop to 0.06
- when reconnecting the LSM it made the amps go up to 0.37 for about a minute, and then 0.07 again
- the BCU has 3 connectors, so I tried pulling them 1 by 1, beginning with the smallest one
- pulling the medium plug on the BCU made the amps go down to 0.03 (same as fuse 5)

- After reading that fuse 5 (which was the only one who made a significant difference) was either for the BCU or for the wipers, I decided to pull the black connector on the wiper-motor underneath the windscreen. This made the amps go down to 0.03
- reconnecting the black plug (with 4 wires) on the wiper motor, made the amps go up to 0.38 at first, but then down to 0.07 again
- the wiperblade motor also has a white plug, that has 2 wires that go to the motor, which made no difference. The amps stayed at 0.07
- I put the key in the ignition and switch on the wipers, they work perfectly fine and smooth
- After taking the key out, having a cup of coffeee and checking back with the car. The amps where down to 0.07 again. Pulling the wiper blade motor (black plug, not the white one) still made the amps go down to 0.03 amps.

After using Google I found
https://the75andztclub.co.uk/forum/s...d.php?t=110650
For Stuadh it was enough to change the battery. But I already did this in december when the previous battery died in the same way as the current one has. It is also clear that my car using to many amps (0.07 which should be 0.03/0.04)


Now, there are 2 things I am slightly worried about:
1. There where a few random moments when the amps went up without any clear reason. If this would happen every now and then, it wouldn't really be very helpful in trying to keep the battery alive. However, I have been unsuccesful in repeated the random spike, and it doesn't seem to happen at predictable intervals
2. Why, and how, can the wiper motor use amps? I thought this would just be like some other simple systems: it gets power, it does something, it doesn't get power it doesn't do anything. Kinda like a lamp. A switched off lamp shouldn't be able to drain power as the switch prevents it from getting any electricity.

I honestly don't understand where to go from here. It would be tempting to just pull the wiper motor till I get my hands on a new wiper motor, but I would like to eliminate the possibility that it is caused by something else. Googling around I have seen mentions of a BCU that keeps checking if the wipers are at the correct position, which is a fault in the BCU and not in the wiper motor. I have also read stuff about a bad earth connectiong causing the wiper motor to not function properly and not knowing when to shut off. Others have said that the wiper motor has to understand when it is back in "down" position, which is controlled by different systems/sensors in different cars.
I'm even inclined to think that the drain on the wiper motor is a symptom of something else, and might not be the main culprit. In theorie, that could mean that a new wiper motor doesn't solve the problem?
Unfortunately, I do not know how to test these things and how to eliminate any other possibilities. So, I don't really know where to go from here (apart from replacing the wiper motor and/or refurbishing it myself).
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Old 7th June 2020, 07:58   #45
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I decided to pull the black connector on the wiper-motor underneath the windscreen. This made the amps go down to 0.03 ...
You may have something here Vinnie. From the MGR wiring diagram it appears that the black connector has 4 wires. With this connected to the motor, the wipers switched off and the car's systems "asleep", is it possible to measure a voltage between the red/light green wire and earth (the black wire)?

If this is impractical I have a plan B.

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Old 7th June 2020, 08:39   #46
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Not a problem. I shows a few "naked" pieces of metal to put the multimeter on. So I tried all wires.

1 = brown (thin)
2 = red/green (thick)
3 = green/blue (thick)
4 = black (thick)

(image is a bit large)
https://scontent-amt2-1.xx.fbcdn.net...81&oe=5F0123FA

With the lead recently connected (amps at 0.38)

1 + 4 = 0.4 to 0.6 (keeps changing)
1 + 3 = 0.2 to 0.3 (keeps changing)
1 + 2 = 0.05 to 0.1 (keeps changing)
2 + 4 = 0
2 + 3 = 0
3 + 4 = 0

Waiting for several minutes (amps at 0.07)

1 + 4 = 0.1 to 0.2 (keeps changing)
1 + 3 = 0.2 to 0.3 (keeps changing)
1 + 2 = 0.08 to 0.1 (keeps changing)
2 + 4 = 0
2 + 3 = 0
3 + 4 = 0

For reference, the motor itself (the white plug going directly to the electric motor) has 2 wires, that are connected to wire 2 and 3.
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Old 7th June 2020, 09:58   #47
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Thanks Vinnie. The voltage between pins 2 & 4 is what I was interested in and 0v is fine. Back to the drawing board.

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Old 7th June 2020, 10:51   #48
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Lol, I was really hoping you would say: replace the gear unit and you'll be fine again haha.

Not that easy apparently . Still, i feel om the right track with this. Why does disconnecting gives me 0.03 amps less? Where does it come from?

Maybe i should repeat all measurements with the wiper motor disconnected? Might as well...
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Old 7th June 2020, 12:33   #49
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Just redid the measurements, but I only took the one that made any difference in the previous test. So if the previous didn't show any change at all, I skipped that one. The main difference was that I disconnected the wiper motor.

When pulling the middle large fuse underneath the master fuse (50a), the amps would go from 0.07 to 0.03. When I pulled it now it stayed at 0.03.

Everything else in the engine bay would just make the amps stay at 0.03. Nothing made it change.

In my previous test, I pulled fuse 5 in the interior. This made the amps go from 0.07 to 0.03. This time I started with 0.03 in rest, and pulling the fuse didn't make it go any lower. Instead, the meter switched a few times to 0.04 and then back to 0.03. I think this means that the amps where just between 0.03 and 0.04, such as 0.035 or something.

Pulling fuse 8 in the interior made the amps go from 0.07 to 0.06. This time it stayed steady at 0.03.

Pulling fuse 20 made 0.07 change into 1.18 the previous time. This time it went from 0.03 to 1.01.

The previous time, when I pulled the middle size connector from the BCU, it went from 0.07 to 0.03. This time it just stayed at 0.03. Pulling the largest connector made everything go to 0.00.

Pulling the smallest connector on the BCU made it stay at 0.03.

My thinking now is:
- if I pull anything (besides the wipers) the amps stay the same or don't change a lot.
- Pulling the BCU makes no difference, unless I pull the connector that also powers the wipers.
- When I reconnect the wipers, the amps go up to 0.07. Which nothing else does.

I really don't understand what is going on now...

However, another thing I was thinking about. I have TOAF, and I read that the BCU window also gives insight in the control for the wipers. Might be worth a try. Downside, TOAF doesn't work when the car is in rest. I'll need to turn the key to make TOAF work.
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Old 7th June 2020, 14:00   #50
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Well, the BCU had quite a few errors . Some are probably due to the low voltage it has seen several times.

https://scontent-ams4-1.xx.fbcdn.net...6f&oe=5F03ACD7
(kinda large image)

And I also checked the IPK, mainly out of curiosity. Which also had a fair few errors.

https://scontent-amt2-1.xx.fbcdn.net...c6&oe=5F021693

I cleared the errors after taking these photo's. When I got out of the car, it had zero errors left (check a few times with "read").

I also checked the settings, and I didn't see anything weird.
I didn't change anything, because I'm not 100% sure on what these options all do. But I did check whether the rainsensor was active (I don't have one) and it was disabled. I checked all the settings for the wipers, and didn't see anything weird or wrong. Everything looked logical to me. I wondered what would happen if I turned off "auto park wipers", but I decided not to do anything without somebody on this forum confirming that this might play a park.

I did notice I had 2 aribags errors, both the passenger seat. So I cleaned the connectors and the error didn't come back.

The battery is now back on the charger (again...).
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