donpb

Yesterday my car was in the pouring rain all day while I was at work. I got off work and drove home just fine even though it took me an hour to get home and was pouring rain. I got up to go to work the next morning and my car wouldn't turn over. I immediately suspected the battery. Called AAA and they took forever to come and the guy said the battery was fine. He tried forever to jump it but failed, repeatedly. I knew he couldn't jump it with his jump pack or his truck battery. He even hooked them both up together and no go.

He left. I looked at the battery and didn't notice anything at first. Then I used a flashlight and saw my battery had an inch or so deep of water surrounding it. Egads. I took my fluid extractor and pumped a good quart of water out. Then the battery measured 8.5V. AAA came back and still could not jump it. I then went and bought a new battery.

Then the car sat stuck at the BMW logo acting all strange. Finally the car decided to start for the first time. Then not start. Then sometimes it starts. Other times when I try to start it or just put the key in, iDrive display will turn off. Its acting really crazy. I'm thinking water could still be somewhere but I can't tell where. Help!

FormerE30Owner

Look in the trunk in the spare tire well. Water could be there, flooding some electronics.

donpb

I looked in there but didn't take the spare tire out.

I didn't know any electronics were under there. Most of the electronics I see are in the sides of the trunk and high up.

535xrayindigo

donpb

I just checked by removing the spare tire and all of the foam pieces. There are no electronics under there and also its bone dry.

535xrayindigo

FormerE30Owner

You might have to revisit the battery location. There are many fuses and relays situated in that area and some might have been wet by the water getting into the battery well etc..

MysticRob

I'm learning all about this myself recently. Just purchased an E61 from Concord and discovered a 1/4" of water in the battery well in the right rear, and enough water in the spare tire well to float the styrofoam that holds the various electronic modules back there. I had 2 blocked sunroof drain hoses in the D-pillars (aka rearmost column where hatch is) at the bottom, and left hose was loose on the nipple that attaches the hose to the sunroof drain channel up in the headliner area. Used gasket maker to seal hose to nipple, blew out all the gunk, and no longer have any leaks. Lucky I got to it before things shorted. I also had to clear the 4 different drains in the engine compartment and checked the 2 front sunroof drains, which were okay, and that drain near the front door hinges (on the wagon anyway). Use compressed air to blow dry the fuse panel and anything else back there.

Previous owner has maintenance receipts showing 12V batteries being replaced, remote fobs not working, and rear glass hatch not functioning, all intermittent issues, which is all likely related to water ingress back there and in the hatch electronics. Recommend you look hard for sunroof and other leaks, plus use a water hose to test everything. Water and electronics do NOT mix well.