E53 2001 X5 - faults in rear/brake lights

[yo_clarkie 0]

So, a wee problem:

Its not a great photo, and the tail lights are after market. The top red lights on each side are the tail lights, the red lights one down are the brake lights. The brake is not depressed in this photo.

IF I turn headlights on I get the :Check Tail Lights" & "Check Stop Light" and the bottom left comes on at about 50% and the bottom right is very slightly flickering.

Current plan is to pull the Trailer Controller to see if its interfering in any way and then pull the LCM if the problem persists. According to the interweb these things can munch the MOSFETs that do the actual power switching, but usually the headlight ones (which are higher rated). Not found a case of the rear's going BUT the after market lights have the rear/stop bulbs in the upper position and both filaments running (not impressed!), which could I guess overload the chip in the LCM. Fix will be to replace the chips in the LCM and take the tail lights out to the range for a little "adjustment"

So how is my logic? Any other suggestions?

Edited April 2, 2011 by yo_clarkie

[kiwi535 538]

have you got the original lights still,swap em back to see if the system is sound at this time?

[hotwire 352]

Dave , could be a fault in the LCM

Has the fault just developed or been present since you have had?

I can't recall on the X5 the OE lamp configuration in comparison to aftermarket:-

e.g. How many tail filaments per side, I suspect only one brake. I see the hi stop not going, although this is a different LCM circuit to L & R brake lights.

Also - which are rear fog? Has it one each side? Are they turned on?

I would remove each bulb & check for correct fit, also if dual filament stop/tail - make sure you dont have a faulty bulb - shorting between filaments

[yo_clarkie 0]

Dave , could be a fault in the LCM

Has the fault just developed or been present since you have had?

I can't recall on the X5 the OE lamp configuration in comparison to aftermarket:-

e.g. How many tail filaments per side, I suspect only one brake. I see the hi stop not going, although this is a different LCM circuit to L & R brake lights.

Also - which are rear fog? Has it one each side? Are they turned on?

I would remove each bulb & check for correct fit, also if dual filament stop/tail - make sure you dont have a faulty bulb - shorting between filaments

Thanks - all good advice, will try this stuff out. I have had the car 4 days and the fault has been here all that time. No indication from the previous owner that the problem exists.

The brakes shouldn't be on in this photo (the pedal is not pressed). I will pick up a new set of bulbs on the way home tonight and try them out - would never have thought to do that (since they are producing light) - if its that simple I will send you a bottle of scotch!

I don't have the OEM lights, but I can easily (using some wire and clips) simulate the OEM wiring setup - which I will do after replacing the bulbs.

Under normal (OEM) operation (UK/Aus/NZ spec) it should be:

Top: Indicator

Middle: Tail

Bottom: Tail / Brake

The after market ones I have are for the North American market (I think)

Top: Indicator

Middle: Tail / Brake (wired to operate togeather as TAIL)

Bottom: Brake

(this means the bulb holders have been swapped over (and only fit one way in both light setups)

Reversing lights and fog lites are on the tailgate and are unchanged (i.e. OEM BMW). They work fine.

The brake lights (when brake pressed) come on at a slightly different rates left to right (could be different bulbs I guess), but that and the partial activation when the parking lights are on is what gived me a sense its the LCM.

Long shot would be the trailer controller that picks up the feed to the lights as an input and then switches its own power to the trailer and reports back via iBus.

Edited March 29, 2011 by yo_clarkie

[yo_clarkie 0]

Start with trying a standard OE light if it works fine then the aftermarket ones are the problem not the car

I don't have them, but I will make up some leads that simulate the OEM wiring and see where that gets me. Thanks

[yo_clarkie 0]

have you got the original lights still,swap em back to see if the system is sound at this time?

I don't but I can simulate the wiring and will try that

[hotwire 352]

Thanks - all good advice, will try this stuff out. I have had the car 4 days and the fault has been here all that time. No indication from the previous owner that the problem exists.

The brakes shouldn't be on in this photo (the pedal is not pressed). I will pick up a new set of bulbs on the way home tonight and try them out - would never have thought to do that (since they are producing light) - if its that simple I will send you a bottle of scotch!

I don't have the OEM lights, but I can easily (using some wire and clips) simulate the OEM wiring setup - which I will do after replacing the bulbs.

Under normal (OEM) operation (UK/Aus/NZ spec) it should be:

Top: Indicator

Middle: Tail

Bottom: Tail / Brake

The after market ones I have are for the North American market (I think)

Top: Indicator

Middle: Tail / Brake (wired to operate togeather as TAIL)

Bottom: Brake

(this means the bulb holders have been swapped over (and only fit one way in both light setups)

Reversing lights and fog lites are on the tailgate and are unchanged (i.e. OEM BMW). They work fine.

The brake lights (when brake pressed) come on at a slightly different rates left to right (could be different bulbs I guess), but that and the partial activation when the parking lights are on is what gived me a sense its the LCM.

Long shot would be the trailer controller that picks up the feed to the lights as an input and then switches its own power to the trailer and reports back via iBus.

Also, just thinking Dave - not sure but the X5 OEM lights may be using a varying voltage to a 21 watt bulb to control tail & brake brightness - as with the E46

[yo_clarkie 0]

Also, just thinking Dave - not sure but the X5 OEM lights may be using a varying voltage to a 21 watt bulb to control tail & brake brightness - as with the E46

Cheers, ran every test I could think of and get to the same place, that the LCM is faulty. cr&p!

Will pull it apart and buy some chips, hopefully that will fix it.

Thanks for the help. Dave

[yo_clarkie 0]

SOLVED!!!

Also, just thinking Dave - not sure but the X5 OEM lights may be using a varying voltage to a 21 watt bulb to control tail & brake brightness - as with the E46

BINGO! In the photos the left side is correct and you are right, the lower unit gets brighter when you press the brake (never seen anything like this before). The right unit (that I thought was working correctly) was the one with a fault (both bits should be on with taillights on), it had blown a hole through the metal trace on the back of the light fitting. Sandpaper and a small blob of solder and its all working perfectly again!!!!!!!!!!!!

Edited April 2, 2011 by yo_clarkie

[*Glenn* 854]

SOLVED!!!

BINGO! In the photos the left side is correct and you are right, the lower unit gets brighter when you press the brake (never seen anything like this before). The right unit (that I thought was working correctly) was the one with a fault (both bits should be on with taillights on), it had blown a hole through the metal trace on the back of the light fitting. Sandpaper and a small blob of solder and its all working perfectly again!!!!!!!!!!!!

For a short time. The plastic behind the metal circuit board collapses with the heat of the the bad circuit. The only way to make a sure fix is to replace the tail light. This is a common problem. .. It may be OK for a while though...time will tell

[yo_clarkie 0]

For a short time. The plastic behind the metal circuit board collapses with the heat of the the bad circuit. The only way to make a sure fix is to replace the tail light. This is a common problem. .. It may be OK for a while though...time will tell

Bugger.

I might put some LED bulbs with resistors in, they will draw significantly less power for the same light and take some of the load off the connectors. Worth a try I guess.

Actually, that won't work with the dual voltage thing. Will repair if it fails again, or replace I guess. Poor design.

Edited April 5, 2011 by yo_clarkie