2001 X5 Electrical Problems

[dawgman]

My car is acting really strange and I am trying to figure it out. All of the brake lights started coming on, so I replaced the brakes, which had about 60k miles on them. I replaced 2 of the sensors and those lights (DSC, ABS) are still on. I was hoping new brakes and sensors would solve that problem, but they haven't. My stereo (aftermarket) cut off the other day when I tried honking the horn, which also stopped working. Now, occasionally when I try honking the horn, all of the interior lights come on. The trans. fail program and check brake lights keep popping up and I know the transmission is fine because I just spent $5k last month to replace it. On top of that, none of the switches by the seat heaters work and the rear wiper stopped working along with the rain sensing part of the front wipers. This all happened in the last few days. The stereo will some times power on when the car starts, and other times it will not. It also shuts off during the drive followed by the trans. fail message at the same time. Sometimes when I turn on the seat heater, it will turn the stereo will turn on.

Serious gremlins going on right now. I have spent over $7k in the last 2 months on this car and am really hoping I don't have to spend a few more thousand on new computers. I replaced the battery hoping to solve the problems, and it did not unfortunately. Any ideas would be very appreciated. Thanks.

[mrbmwx5]

you need to reset the brakes light after you replace the pads,
the rear tail light keep saying check brake light you have an melted socket in the tails light ASSEMP..
and the rest some one will chime in
GL.

[dawgman]

I also noticed that my 3rd brake light the other night was on full time even when I wasn't hitting the brakes.

[supersteve]

Sounds like a bad ground some place. Check the wiring, under the rear floor around the battery, for anything obvious. You may also want to check voltage with the engine off (battery) and with her running (alternater). A failing alternater with low voltage will do wonders.

I would also recommend you clean the contacts on the ignition switch. It sounds really strange, I know. Everything you are talking about goes through a test on start up. The only common denominator for all these systems (other than a ground, the battery and the alt) is the ignition switch. Many problems have been caused by the switch itself.

I would try cleaning it first (no cost other than time). If the symptoms change, for better or worse, install a new switch. They cost about $100.

[KiwiJochen]

i agree, replace the ignition switch. i am 90% sure it will be the cause of all of the problems

[dawgman]

Thanks so much for the help. Can I replace an ignition switch myself? I have no idea where it is or how to replace it. I just replaced the battery hoping that would solve the problem, but it didn't do anything. I was thinking it could possibly be the alternator, but I have had no problems with the old 5 year old battery or the new one starting my car. I would think I would have a hard time keeping a charged battery if the alternator was bad.

That is crazy that a possible faulty ignition switch could cause all of these problems.

Lastly, I have a cracked rear window wiper that needs to be replaced. Is there an inexpensive place to buy these?

[KiwiJochen]

Originally Posted by dawgman

Thanks so much for the help. Can I replace an ignition switch myself? I have no idea where it is or how to replace it.

Absolutely.
Locating it is quite easy: think of where you insert the key to turn on the car. That is the ignition switch. You can replace the electrical part separately from the mechanical part.

Originally Posted by dawgman

I just replaced the battery hoping that would solve the problem, but it didn't do anything.

Should have asked here first. Easy to test the battery.

Originally Posted by dawgman

I was thinking it could possibly be the alternator, but I have had no problems with the old 5 year old battery or the new one starting my car. I would think I would have a hard time keeping a charged battery if the alternator was bad.

Nope. Alternator will not produce these symptoms.

Originally Posted by dawgman

That is crazy that a possible faulty ignition switch could cause all of these problems.

Not really. The dirty contacts in the ignition switch cause electrical noise on the 12V line.

This is then carried onto the k-bus and i-bus databusses due to the pullup resistor in the instrument cluster

The noisy voltage line causes data corruption on the databus, resulting in databus messages being misinterpreted or not interpreted at all.

Hence devices which are controlled by the databus - almost everything - show strange symptoms.

Replace the ignition switch with a BRAND NEW one, and all your problems will go away.

Easy DIY job, straight forward and simple to replace.

[dawgman]

Thanks. No worries on the new battery, the old one is 5 years old and I do have a few thousand watts pumping through my stereo system. It was due.

So from what you are saying, the electrical part of the ignition switch is also in the steering column? If that is the case, is there anything special to taking that shell off? Should I try to unplug it first and clean it before ordering a new one? I would probably order a new one anyways, but wondering if it might be a short term fix.

[dawgman]

I have taken off the top and bottom pieces around the steering column, but am still not finding where the ignition switch is. Is it down below, closer to the pedals? I ordered the part, but wanted to try and clean out the contacts first to see if that would help. Thanks.

[supersteve]

There is a large plug on the left side of the steering column. It is about 1"x1". Pull that plug off and you"ll be able to see into the switch. A little contact cleaner and/or WD40 and you should be good for a short term fix. The first time I did it it lasted almost a year.