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).