Lighting Control Module Problem?

[jmr3]

I am having some issues and I hope someone can help. I did the brake controller install as suggested on this site and have the following symptoms.

Have left turn signal and brake light on trailer. Have running lights on entire trailer. Have no right side brake lights or right turn signal.

I have verified that this is not a problem with the trailer.

O1, 4.4, with factory tow package and a P3

My wrench thinks it is most likely a lighting control module issue requiring replacement -- not cheap!

Please help!

Thanks!

[TowX]

If the X5 works fine without the trailer connected then it isn't the LCM.

Three thoughts-
1) Have you checked to be sure you've wired the female part of the plug correctly?
2) When you say you have no right side lights is that just on the trailer or on the trailer and the X5? If it's just the trailer, see #1 above. If it's both the trailer and the X5, them maybe you have a faulty trailer light module. The LCM is the box in the right front foot well by the glove box. The Trailer module is back by the spare. You do have one of the factory BMW trailer light modules don't you?
3) How did you wire the electric brake pickup for the P3? Most of us tap off the LCM for the brake input. If that was incorrectly done it may have shorted the right side circuit. Try pulling the plug on the back of the P3 and see what happens. Or you could have a bad P3 thought I've never heard of that happening. Usually someone unfamiliar with the Hall effect wiring on the X5 just taps into one of the brake light wires for the P3 and wipes out the lights. Can't be done the GM way on our vehicles.

[jmr3]

TowX,

Thank you very much for the reply.

The lights on the X function correctly with and without the trailer. I have a factory installed tow package with tow module. I tapped off the LCM as instructed by the threads on this board and am pretty sure (99.9%) I did it correctly.

I will try unplugging the P3 and also tracing power to the female plug.

Thanks again!

[TowX]

Keep us posted on your progress. But if the X works fine with and without the trailer hooked up, and it's just the trailer lights that are off, I would have to question the wiring at the plug. There is a "standard" way to wire a trailer and a recepticle, but someone may have gotten either of them incorrect. I always check the pins on the receptacle for function, then make sure the same pins in the trailer plug correspond.

Keep in mind on most trailers that the right (and left too) brake light filament flashes to make the blinker. So if the filament was bad, neigher brake or blinker would work. I know it's stating the obvious, but did you check the bulb? Simple way to check- swap bulbs side to side. Also check the right side trailer light ground wire.

The other thing to do is take a circuit tester or a volt meter, and with your right blinker turned on (trailer unplugged) check for current flashing at all the pins in the receptacle. If you have current, take a jumper wire from that terminal and start touching to the trailer plug until your right trailer blinkers flash. Then see if the pins correspond.

All simple things to check, and by process of elimination you should find your problem.

[NJ04e53]

sorry to ask this, but where is the LCM located? Thanks

[sarb]

Originally Posted by NJ04e53

sorry to ask this, but where is the LCM located? Thanks

Check this link.
http://www.xoutpost.com/bmw-sav-foru...-location.html
always use the search button its pretty useful lol

[NJ04e53]

weird.. I have been searching and never came up with this.. thanks btw..is this same for the 3.0?

Originally Posted by sarb

Check this link.
http://www.xoutpost.com/bmw-sav-foru...-location.html
always use the search button its pretty useful lol

[sarb]

Originally Posted by NJ04e53

weird.. I have been searching and never came up with this.. thanks btw..is this same for the 3.0?

Yes all E53's

[jmr3]

Well I found my problem. I connected the brake controller to the input of the LCM and not the output. It was fun figuring this out -- not!

Thanks to all who helped!