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2007 E61 water, electrical, air suspension adventure

1542 Views 6 Replies 3 Participants Last post by  eribbs
Hi Everyone,

I have been using this forum quite a bit for help with my cars, so I felt that it would be good to share my recent experience in the hopes that it might help someone else down the road! This will probably be lengthy, but I took a lot of pictures along the way and want to get it all down in a few posts. I acquired a 2007 E61 530xi that belonged to my grandparents (I even helped my grandfather fill out the custom order form when he went to buy it back in 2006!), and boy did I get thrown into the depths of E61 woes quickly. At this point, I am sure everyone is aware of the sunroof drain issues in these, and that is where this experience began.

We had an ice storm here that started off with a good amount of rain as the temperature dropped (so pretty much everything that was wet turned to ice). My wagon, which spent the vast majority of its life in the garage, happened to not have a spot indoors for this weather - I believe the wet grommets at the end of the drain tubes in the D pillars froze shut then filled up with water/ice. As the sun melted the ice on the roof, the water had nowhere to drain until the drain tubes fully defrosted, causing the dreaded flooding of the trunk area of the car. I came to find out later when I removed the grommets that there was essentially no dirt built up on the tubes (again, garaged for all its life), so that is really the only way I could see the flooding happening.

The drains are located in the far rear corners on the other side of sheet metal from the tail light connections. On the right side, it sits behind the fuse panel tucked around the corner. I ended up pulling the tube out with a good amount of force and the grommets popped out and down to the ground (the right side fell into the underside cover of the air compressor).

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As I didn't expect to have the water build up when the ice melted, I got in to move the car and was greeted by a barrage of warning lights and a deep sinking feeling as the rear of the car lowered to the ground. There began the investigation in the trunk. The carpet was damp when I opened the tailgate, so I started pulling out everything I could remove from the rear to dry out in the sun. When I pulled out the spare tire, I noticed that the lining was not only damp, it was soaking wet. Sure enough when I pulled out the lining, I found the styrofoam molds that house the electronics in that terribly space-efficient and drainless location bobbing up and down in a few inches of ice-cold water. Sigh. I figured it was done for at this point, but that also gave me the "confidence" to just take a stab at fixing it myself, as I figured I couldn't make it much worse than it already was!

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When I tried closing the tailgate, I found a few more symptoms to add to the growing list of concerns.. augmented by the quick death of the massive year-old battery shortly thereafter. In the end, here is what I was faced with:
  1. Spare tire well full of water
  2. Tailgate didn't fully latch when closing
  3. Rear wiper was unresponsive and stuck in a mid-swipe position (why it tried to move is a mystery to me, though I heard that sometimes they move on their own when the battery gets low...?)
  4. Rear air suspension sitting down as low as it could go, with no audible attempt to fix itself
  5. TPMS failure warning
  6. Dead battery
Continued...
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After removing all the water from the spare tire well and the small amount around the battery, I hung the wire harness out to dry and found a small handful of fuses that had blown in the rear fuse box. I replaced them all and got a replacement battery to see if it was that simple of a fix. It wasn't. While all but one replacement fuse survived the next car start, I still didn't have the tailgate latch and wiper functionality. A little research led me to the control modules that were stored in the well (and thus took a swim for a bit). I took them all in the house and disassembled them to take a look at the circuit boards. Sure enough each of them had visible corrosion, though they didn't look terribly damaged. Jumping out off the ledge, I looked up ways to clean circuit boards and used the following processes:
  1. Cleaned them with an aerosol electronics cleaner (CRC QD Electronic Cleaner I got at Home Depot)
  2. Made a thick paste of baking soda and distilled water, and lightly but thoroughly scrubbed them clean with a cheap soft toothbrush (from Target)
  3. "Rinsed" off the baking soda residue with 91% isopropyl alcohol (from Target) - ended up dipping each in a shallow bowl of it and using a second soft toothbrush to clean them
  4. Used the CRC Electronic Cleaner again to spray off any remaining liquid and residue - the CRC spray dries extremely quick, so it works great in this application
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I must say that the results were great with this! When I hooked them back up, the rear wiper and the soft-close tailgate latch started working again! Sadly, the air suspension and TPMS did not. So I trudged on and did about as detailed of an investigation of the wiring harness throughout the rear of the car as I could. I found a bit more corrosion on the three relays and their connectors in the well, so I cleaned the connectors with CRC and a toothbrush and replaced the three relays. The rest of the wiring looked good in there, so I tried starting the car again. Again I got no response from the air springs or TPMS. It's worth noting that I picked up a 25-30 pack of 40 amp fuses, as this was the one that remained an issue in slot 52, feeding the air suspension compressor. Each time I tried to clean or fix something, I would check by starting the car and blowing the fuse again - kind of a waste, but a relatively cheap way to test as I moved along.

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Continued...
My next step was to move under the car to the air compressor itself. When I pulled off the protective panel on the underside, I found some old damage to the foam that surrounds the compressor. It appeared that a mouse had taken up residence in there at some point in the last 15 years. The majority of the damage was to the foam itself, though even that wasn't very bad and there was no need to replace it. What I did come across was a half chewed wire feeding the air compressor! Ah-hah! I had found a good reason that the compressor was not turning on and blowing the fuse. Instead of going through the trouble of replacing wires, I figured I could repair this spot without too much difficulty. I snipped the wire and exposed the copper threads on each side, then used a simple soldering gun to solder the two sides together. I was satisfied with the work and wrapped it up, put in a new fuse and turned on the car. The fuse blew again and still no compressor. Sigh. The next step was to check the compressor itself.

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When I went to pull off the electrical connector to the compressor (the one with the big wires that power it), I was met with a LOT of resistance. After a lot of wiggling and twisting with as much flexibility as the connector allows, I finally got it off. When I looked at the end of it, I saw that part of the plastic had started to melt at some point, and appeared to melt to the receiving end of the connector on the compressor. Weird, but a good indication that there was an electrical issue with the compressor. With the compressor disconnected, I put in a new fuse and turned on the car. To my delight, the fuse did not blow - I think that essentially isolated my problem to the compressor itself. I got out my voltage and continuity tester (Klein brand from Home Depot) and tested the leads in the connector on the compressor. I got the warning of a closed circuit - the compressor was the culprit, at least from what I could tell, as this was pretty much all new territory for me.

I looked around online for a replacement compressor (because there was no way I was going to buy the $1150 one from the BMW dealer nearby) and decided on the AMK replacement that I found on PartsGeek.com, as AMK manufactured OEM equipment for BMW (and ~$550 was a much better deal than the "dealer" could provide). While the compressor shipped, I took a look at the melted connector and carefully carved away the melted plastic around the entry for the lead on the compressor. Luckily, everything looked ok beyond the melted tip, so I decided it would work for the new compressor (partly based on logic, partly based on zero interest in running new wires or replacing the wiring harness.. plus I couldn't find the connector for sale by itself).

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Continued...
The new compressor arrived a couple days later and I immediately went to work switching it out. I was pleasantly surprised to find out that the original compressor on the car was actually manufactured by AMK, and even featured the AMK stamp on the end, just like my replacement. Apparently BMW stickers cost $500-$600 to stick on to the sides of AMK compressors. The part I purchased came with the mounting bracket and the solenoid valve block pre-assembled, so all I had to do was move the mounting rubber grommets (?) from the old to the new, then hook up the air lines and electrical connectors. The new unit even came with a new braided air hose; I haven't had leaking issues with the old one (also the braided version), so I reused my old line for now and am saving the new one for a rainy day. In all, it took me about an hour to remove and replace the compressor. When I finished that up, I went to start the car again as a test.... the air compressor kicked it and the car lifted itself up like it just woke up after a nice relaxing week of beauty sleep. The suspension was fixed!

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At that point all I had to do was reassemble the interior and take the car for a drive to clear out the error messages that showed up after disconnecting the battery. I have not addressed the TPMS error message I am seeing, but at least for that, I can see that the tires are full and the car drives normally again. This type of investigation and car repair was a first for me, but in the end I actually learned a lot through forums like this and through trial and error, so I am very glad I took on the challenge... the icing on the cake was when I thought how much money I probably saved by not taking it to the dealer right off the bat!

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I hope that my experience and documentation here might help someone else in the future, or at least encourage others in their own repair adventures.

Erick
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Reactions: kd7iwp
Nice work! Very diligent and thorough investigation.......not sure I could/would do the same.
The new compressor arrived a couple days later and I immediately went to work switching it out. I was pleasantly surprised to find out that the original compressor on the car was actually manufactured by AMK, and even featured the AMK stamp on the end, just like my replacement. Apparently BMW stickers cost $500-$600 to stick on to the sides of AMK compressors. The part I purchased came with the mounting bracket and the solenoid valve block pre-assembled, so all I had to do was move the mounting rubber grommets (?) from the old to the new, then hook up the air lines and electrical connectors. The new unit even came with a new braided air hose; I haven't had leaking issues with the old one (also the braided version), so I reused my old line for now and am saving the new one for a rainy day. In all, it took me about an hour to remove and replace the compressor. When I finished that up, I went to start the car again as a test.... the air compressor kicked it and the car lifted itself up like it just woke up after a nice relaxing week of beauty sleep. The suspension was fixed!

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At that point all I had to do was reassemble the interior and take the car for a drive to clear out the error messages that showed up after disconnecting the battery. I have not addressed the TPMS error message I am seeing, but at least for that, I can see that the tires are full and the car drives normally again. This type of investigation and car repair was a first for me, but in the end I actually learned a lot through forums like this and through trial and error, so I am very glad I took on the challenge... the icing on the cake was when I thought how much money I probably saved by not taking it to the dealer right off the bat!

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I hope that my experience and documentation here might help someone else in the future, or at least encourage others in their own repair adventures.

Erick
  • Like
Reactions: eribbs
Good on you for solving the problems. A couple of suggestions.
Carry spare fuses in the car.
Replace the relay if you have not done so.
Replace the complete intake hose with a length of fuel line because the section under the fender liner will develop cracks and then water will be sucked into the compressor, causing it to seize.
Thanks! I generally have at least one of each fuse in the car (I had the original set from BMW even). I now have good number of each waiting as backup!
I replaced the relays when I cleaned up the wires and connectors as a precaution, they aren't terribly expensive so it was definitely worth just getting new ones.
I will add the fuel line substitute to my task list for the car, now that I'm back in working order, good idea!
Good on you for solving the problems. A couple of suggestions.
Carry spare fuses in the car.
Replace the relay if you have not done so.
Replace the complete intake hose with a length of fuel line because the section under the fender liner will develop cracks and then water will be sucked into the compressor, causing it to seize.
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