E85 2.5 Battery light, headlight failure

Joël D. · 12-12-2020, 03:23 PM

Hi guys,

When I drove home last night, the Battery light came on. 20 minutes later some other (yellow) warning lights followed, including power steering failure. When I restarted the car (no hesitation of the starter at this moment) all the problems were gone, except a bulb failure (headlights). At the moment everything works, except the headlights (both of them). I replaced the battery, just in case, however the problem still exists.

I also checked the current to the battery, but no current was provided. So, I assume the problem lies in the alternator, however, that doesn't explain the headlight bulb failure for me. Also checked the fuses, but couldn't find anything wrong here.

Is this a common issue? I haven't really driven the car since, so I assume that if I do the battery light will come on after it is drained again. But what prevents the headlights from turning on? Will replacing them solve the issue (and why did both of them die at the same time?) or is there something else wrong?

rsutoratosu · 12-12-2020, 10:07 PM

Need a scanner.. could be either speed sensor, steering angle sensor or reset of steering angle sensor..

If the bulb was never changed, it might be time. I had bulb light when I park to pick up sometime and came back after a few min, it goes away if i turn it off/on. After I change bulbs, it never happen again. Unless the ballast ? assume you have HID ?

Sometimes wiring breaks, hope not that..

Joël D. · 12-13-2020, 08:48 AM

Looks like just the bulbs failed because of the alternator. 12V is still supplied, so no problems there.

Gonna change the alternator next week and hopefully we'll be golden.

Angelito · 12-14-2020, 01:13 PM

You can just change the voltage regulator on the back of the alternator and save some $$. You will need to see if your voltage regulator is made by Valeo or Bosch and order the right one. Mine was Valeo and I bought the voltage regulator for $49 a few years ago, replaced it and had no alternator issues since (one of the copper leads had more wear than the other).

p.s.-the biggest pain

was taking the alternator out, the actual voltage regulator is held on by 3 small screws.

12-12-2020, 03:23 PM	#1
Joël D. Registered 5 Rep 3 Posts Drives: Alfa Romeo 155/BMW Z4 E85 Join Date: Dec 2020 Location: Holland iTrader: (0)	E85 2.5 Battery light, headlight failure Hi guys, When I drove home last night, the Battery light came on. 20 minutes later some other (yellow) warning lights followed, including power steering failure. When I restarted the car (no hesitation of the starter at this moment) all the problems were gone, except a bulb failure (headlights). At the moment everything works, except the headlights (both of them). I replaced the battery, just in case, however the problem still exists. I also checked the current to the battery, but no current was provided. So, I assume the problem lies in the alternator, however, that doesn't explain the headlight bulb failure for me. Also checked the fuses, but couldn't find anything wrong here. Is this a common issue? I haven't really driven the car since, so I assume that if I do the battery light will come on after it is drained again. But what prevents the headlights from turning on? Will replacing them solve the issue (and why did both of them die at the same time?) or is there something else wrong?
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12-12-2020, 10:07 PM	#2
rsutoratosu Captain 114 Rep 779 Posts Drives: Z4 3.0i Join Date: Mar 2011 Location: Chicago, IL iTrader: (0)	Need a scanner.. could be either speed sensor, steering angle sensor or reset of steering angle sensor.. If the bulb was never changed, it might be time. I had bulb light when I park to pick up sometime and came back after a few min, it goes away if i turn it off/on. After I change bulbs, it never happen again. Unless the ballast ? assume you have HID ? Sometimes wiring breaks, hope not that.. __________________ -Roranji
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12-13-2020, 08:48 AM	#3
Joël D. Registered 5 Rep 3 Posts Drives: Alfa Romeo 155/BMW Z4 E85 Join Date: Dec 2020 Location: Holland iTrader: (0)	Looks like just the bulbs failed because of the alternator. 12V is still supplied, so no problems there. Gonna change the alternator next week and hopefully we'll be golden.
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12-14-2020, 01:13 PM	#4
Angelito BMW Enthusiast 29 Rep 59 Posts Drives: 07 E86 Z4MC, 05 E46 330i Join Date: Oct 2015 Location: Texas iTrader: (0)	You can just change the voltage regulator on the back of the alternator and save some $$. You will need to see if your voltage regulator is made by Valeo or Bosch and order the right one. Mine was Valeo and I bought the voltage regulator for $49 a few years ago, replaced it and had no alternator issues since (one of the copper leads had more wear than the other). p.s.-the biggest pain was taking the alternator out, the actual voltage regulator is held on by 3 small screws. Last edited by Angelito; 12-14-2020 at 01:20 PM..
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