Z4 electrical issue, brake lights stay on, radio faults...crazy!

I

I2cater

Member
 South Wales (Cardiff)
Hi, really new to Z4's, I have a 525d, which has been faultless. Unfortunately I cannot say the same of the Z4. The car went in for a new starter motor the other day, on picking the car up the garage tell me that they have noticed the brake lights were staying on, they tried changing the switch at the pedal twice, as they thought the first switch may have been faulty, they are lost with where to go next! On driving the car home, the bulb warning light and Airbag light were both on, I also noticed a few LED bulbs out on the Third brake light, also, the steering controls for the radio doesn't work, and the radio display shows this strange message ----/---- Can anyone shed any light on what could have happened, could it be the fault of the LED bulbs not working?? Canbus?? Help!!!
 
Guessing they disconnected the battery. Could be an earthing issue. Radio something ---- is because the time needs to be set. I would look at the battery connections first along with the condition of the battery.

As above though if all was ok when you took it in then the garage should be sorting.
 
Garage has apologised, but as he said, all he did was disconnect the battery! Which had to be done to change the starter. Will get the battery checked to eliminate one item, any other thoughts will be greatly appreciated, but this is really strange, and annoying as I can't even drive it. The worst part is that I have a new set of alloys in the conservatory waiting to go on the car, her in doors is most disgruntled!!
 
Sorry to see you first post is to report a problem. You don't say what Zed you have or its age. A defective battery can cause some of the problems you mention. I would certainly check the battery connections and then the condition of the battery as a starting point. Was anything disturbed when they removed the starter motor? Could be some electrical connection was dislodged. The third brake light may well be a separate issue but go with the simple things first and get the battery checked.
 
It's a 2004 Z4 3.0 with less than 80k, it's given me little pleasure in the short time I have owned her (6 months), I have had the sticky steering, AirBag light from passenger seat mat, seat belt buzzer, window motor, MOT failure for bushes on front and now this. And my split rims to refurbish, well I needed to sell a kidney! Could anyone tell me the criteria of what I should expect the battery to be putting out. My 525d has been a total dream over the years, should have lobbed the top of that!!
 
As a very rough guide you should get 12.65 V from a fully charged good battery. You have to disconnect it after its charged and leave it a few hours to get an accurate reading though. If it's less than 12.35 V a change isn't a bad idea. Garage should have a proper battery checker though. Don't pay more than £70 for a new one, plenty online. The brake lights come on when the fuse is blown, have they checked that? With 80k you should start expecting to replace bushes - plenty you can DIY which saves a considerable amount of cash - makes the car feel so much better too.
 
Appreciate your support guys, always looked on the forums in the past for feedback, never needed to post until now! You all do good work and can help the novice owners considerably. I know battery issues can be a problem, previously had a Merc that was in limp mode, wouldn't get out of 2nd gear being an auto, turned out to be the battery, apparently the same characteristics for the E60 BMW. If you were correct and it's the battery (fingers crossed) will it need to be reset, or will it figure that out for itself? And, just looked on Eurocarparts for prices, wow! Huge selection for my specific car, any suggestions on brand and specific Ah rating?
 
Nothing to rest when changing the battery other than the clock and the simple window reset procedure. Doesn't need coding like an E60.
 
Mine was at 75% charge and started being odd, windows wouldn't go back up after opening door occasionally. Varta E44 from interweb shop sorted it, better CCA similar Ah I think, same physical size.
 
Checked the Battery voltage using an OBDII reader, it reads 11.7 volts, is this variance enough to cause problems as suggested? To add insult to injury! had to replace the expansion tank this week as well, not sure whether I will bother to change the wheels at all now!!
 
If that's correct then it's practically flat, surprised you can start up. Better check would be with a multimeter though. Equally the alternator could not be outputting enough to charge it. With the engine running you should get 13.6 V+ (up to about 14.2 V) so check that too. Once a battery has been discharged it will never perform as well in future so probably worth a change, though you'll get by for a while.
 
I think you have a few issues to solve in sequence or at least after the battery is sorted:
Get a new battery once you've completed the tests suggested re the voltage, but it sounds dead. Until done you'll have all sorts of issues
Reset the clock and get rid of that message and reset the windows. so they open and close correctly (These things happen when battery disconnected)
The rear centre brake light is just a faulty unit - buy another one
Brake lights on is as suggested likely a blown fuse. Check and eliminate that
Airbag light can be anything in the circuits, modules, airbags, etc.. Most common cause is turning on the ignition with one or more parts disconnected which trips the light. Needs to go to be reset at BMW, Indy or a local forum member with the right software and if it comes on again diagnosed for which part of the circuit. needs fixing
Steering wheel controls could also be a fuse. Easily blown. If not then proper diagnosis assuming they ever worked and it's not a retrofit wheel that was never set up.

Think that's it to get you started, but nothing serious in your list.
 
Images of battery charge to guide you: Any of the coloured images show how dead your battery is

https://www.google.co.uk/search?q=car+voltage+charge+images&biw=1920&bih=966&tbm=isch&imgil=matcDnRD6FhYvM%253A%253B3j23iCYGLb9jDM%253Bhttp%25253A%25252F%25252Fwww.ukpassats.co.uk%25252Fphpbb%25252Fviewtopic.php%25253Ff%2525253D8%25252526t%2525253D80528&source=iu&pf=m&fir=matcDnRD6FhYvM%253A%252C3j23iCYGLb9jDM%252C_&usg=__wLcXjp-QavC70XG7o-2o1nabFh4%3D&ved=0CDQQyjdqFQoTCJ66lqaksMcCFcp9GgodnaAMhA&ei=vOnRVZ7sEsr7aZ3BsqAI#imgdii=matcDnRD6FhYvM%3A%3BmatcDnRD6FhYvM%3A%3BJzC075WM8er2uM%3A&imgrc=matcDnRD6FhYvM%3A&usg=__wLcXjp-QavC70XG7o-2o1nabFh4%3D
 
Update....Changed battery, no changes to the problem! Got the correct battery before anyone suggests different! Having the same symptoms, but it is eratic! Drove for 3 hours yesterday without a problem, today it's back with a vengeance! Any more suggestions people??
 
Still trying to resolve the problem, checked alternator and battery, all is ok here... Could it be the result of the 4 missing led's on the middle brake light? What do you think guys??
 
I2cater said:
Still trying to resolve the problem, checked alternator and battery, all is ok here... Could it be the result of the 4 missing led's on the middle brake light? What do you think guys??
Click to expand...

No... wouldn't affect it at all !

Only thing I can suggest ....is to look for bad connections , earth straps etc. !
 
The reason I say this, is concern over the CAN bus element! I know it can cause strange errors. Again, drove 2 1/2 hours yesterday without any issues, but when I get home, it all starts again!!
 
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