Its broke AGAIN!!

[Matty_Z4]

It seems to be a good time to revive an old thread of mine with some additional information as it seems there have been others with similar faults in recent times so hopefully this helps others out.

Since this thread was posted the fault has happened once or twice and every time it was water in the gear selector switch connector, this has been sealed up with silicone and goo by my mechanic and this has been good for a while (I will get around to replacing the switch one day - Maybe in the spring/summer next year)

We recently had a bad spot of rain and a small puddle takes out my car again (might have been 3" -4" but across both lanes so no escape). Mechanic sends me to a transmission guy who confirms its an electrical issue and calls in a favour from a mate of his who is an auto electrician. He finds water in the main transmission plug (the one that goes to the TCU? Is that what you call an ECU for a gearbox?) So he has dried that out and sealed it up with liquid electrical tape. Hopefully this will see me through the winter and in the spring I will have another poke around and see if there is a better and more permeant fix. (Photos to come in the spring when I start tinkering again)

https://www.bimmerfest.com/threads/drove-over-water-and-transmission-malfunction.457762/

Not my photos but ones from the above thread, the plug circled in red is the one that connects to the gear position switch and was the one that has been causing me the most problems, this is sealed with silicone and goo so hopefully stays happy until the spring/summer.
The connector circled in yellow is the one that was the problem this time and apparently there is a rubber boot that cracks and falls off (same as a headlight boot)



This is the loom that connects into the transmission showing the grey boot that fails causing water to come in, apparently it is the same boot that BMW use on the headlights so you can remove the connector slip a new boot on and then put the connector back together. again I will take a look and assess in the spring maybe post some photos on here showing the temporary fixes and then get some advise on how best to make it fixed properly. Hopefully the liquid electrical tape and silicone dont cause me a problem next year when I go to fix it properly.

 

[kis]

3 year + update :lol: love it!

Can't you source a new/good condition used cable?

This is my go-to method. As it enables you to tidy up/mod etc as required and then perform a quick swap. Meaning the car is still useable and doesn't have to be off the road (unexpected problems on older cars are pretty much a certainty). So this helps that issue. Plus then you have a spare.

 

[Matty_Z4]

3 year + update :lol: love it!

Can't you source a new/good condition used cable?

This is my go-to method. As it enables you to tidy up/mod etc as required and then perform a quick swap. Meaning the car is still useable and doesn't have to be off the road (unexpected problems on older cars are pretty much a certainty). So this helps that issue. Plus then you have a spare.

Good question it seems you can buy the loom it looks like you have the replace the whole section that goes from the electrics box in the engine bay all the way down to the transmission. Good news is it comes with both of the plugs so that + the gear selector switch should replace all faulty wiring.

Now the million $$ question, do you need to drop the transmission/exhaust to run the new loom in? Has anyone been brave enough to do it?

Check out the postage on the loom though! no UK based sellers on the bay but it might be something to think about next year and in the mean time if one pops up I might grab it.

https://www.ebay.co.uk/itm/295989487818?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=cFp9OUxaRxG&sssrc=2047675&ssuid=&widget_ver=artemis&media=COPY

 

[kis]

Oh blimey. I take that back, doesn’t look quick or simple to do a whole loom!

Can’t comment on the technicality, I’ve not heard of anyone doing something like this before on the Zed. If you search for other cars? The e46 range is my usual go to (I’ve got a M54) as much more info/videos/write ups from that range.

 

[firebobby]

3 year + update :lol: love it!

Can't you source a new/good condition used cable?

This is my go-to method. As it enables you to tidy up/mod etc as required and then perform a quick swap. Meaning the car is still useable and doesn't have to be off the road (unexpected problems on older cars are pretty much a certainty). So this helps that issue. Plus then you have a spare.

Good question it seems you can buy the loom it looks like you have the replace the whole section that goes from the electrics box in the engine bay all the way down to the transmission. Good news is it comes with both of the plugs so that + the gear selector switch should replace all faulty wiring.

Now the million $$ question, do you need to drop the transmission/exhaust to run the new loom in? Has anyone been brave enough to do it?

Check out the postage on the loom though! no UK based sellers on the bay but it might be something to think about next year and in the mean time if one pops up I might grab it.

https://www.ebay.co.uk/itm/295989487818?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=cFp9OUxaRxG&sssrc=2047675&ssuid=&widget_ver=artemis&media=COPY

That's a 2nd hand loom from a car that's done 115k.
I take it, you've tried UK breakers.

 

[Matty_Z4]

3 year + update :lol: love it!

Can't you source a new/good condition used cable?

This is my go-to method. As it enables you to tidy up/mod etc as required and then perform a quick swap. Meaning the car is still useable and doesn't have to be off the road (unexpected problems on older cars are pretty much a certainty). So this helps that issue. Plus then you have a spare.

Good question it seems you can buy the loom it looks like you have the replace the whole section that goes from the electrics box in the engine bay all the way down to the transmission. Good news is it comes with both of the plugs so that + the gear selector switch should replace all faulty wiring.

Now the million $$ question, do you need to drop the transmission/exhaust to run the new loom in? Has anyone been brave enough to do it?

Check out the postage on the loom though! no UK based sellers on the bay but it might be something to think about next year and in the mean time if one pops up I might grab it.

https://www.ebay.co.uk/itm/295989487818?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=cFp9OUxaRxG&sssrc=2047675&ssuid=&widget_ver=artemis&media=COPY

That's a 2nd hand loom from a car that's done 115k.
I take it, you've tried UK breakers.

Not yet, I only looked at the loom to see how expensive/easy it was to swap based off Kis's idea. Looking online it seems the loom replacement could be a pain in the ass as it runs across the top of the transmission and I think the 4 other waterproof plugs are for the o2 sensors not sure why o2 sensors are on a transmission loom? So It means at very least dropping exhaust, drive shaft and hanging the transmission down a smidge to gain access this is a bit too much for my DIY.

What I will probably end up doing is waiting out the winter with a hope and a prayer and with any luck the issue does not pop up any more and the temporary fix has worked for now (Parking node uphill helps it drain if it does happen). Come spring I will have a look at the gear selector switch as that is an easy win to swap out as that will sort some of the wires that have been patched.

I will also take a look at the upper plug that is sealed with liquid electrical tape and see if its possible to remove the connector and replace the rubber boot, just need to figure out what the part number is for the rubber boot. Depending on what the connector and pins look like I might need to replace the loom but I really want to avoid that if possible.

If I did buy a 2nd hand /replacement loom I would look at putting new plugs and seals on the loom which could get expensive because at 115k it is guaranteed to have the same fault as mine.


Replacing the rubber boot in situ could also be a total PITA if the E46 (2004 325i) is anything to go by

 

[firebobby]

Make sure you check your boot for water ingress. When I parked mine nose up, I ended up with water in the left and right sides of the boot.
Luckily I caught it quickly and was able to dry the carpet.

 

[Matty_Z4]

Make sure you check your boot for water ingress. When I parked mine nose up, I ended up with water in the left and right sides of the boot.
Luckily I caught it quickly and was able to dry the carpet.

How often do you check your roof drains? I did mine in the spring there was a bit of water in the drivers side bucket. I also removed the rubber things as they were all gummed up with mud.

Will keep an eye on things and be sure to update this thread.