Trailer light module-Barry

[Barry]

Searched the archives and could not find anything on this module..
I plugged the module into my 535(the plug was there and waiting for it...)but it has done diddly squat-It apparently did work on the donor car..

My question is ,what does this module do-controll-indicate and how can it be made to work..Does it need to be "enabled" as the car was not fitted with it when new??

Im running an oe towbar ,but the wiring does look a bit suspect even though it all works..

[Phil Sanderson]

Hi Barry, I have a '93 540i South African build car fitted with a factory tow pack. If you can post a pic of the module you are asking about I may be able to identify it on my car for you.

regards
Phil

[Dan in NZ]

What do you want it to do? You say all your trailer lighting works, this would seem to indicate that it's doing it's job...

I would guess it extends the functions of the lighting control module to examine the condition of the trailer bulbs. Try removing a bulb and see if you get an error message.

[Barry]

Phil,Dan,Thanks for the reply`s..
Will take a pic today and post..Its situated on the left rear of the boot(trunk)as you open the bootlid.On my car I have the audio amplifier here as well.

Ive removed a trailer light and nothing happens..I was under the impression that it would ding and notify the driver via the dash readout ..
Im a funny bugger-if its there it MUST work..no place for passengers..

[genphreak]

Phil,Dan,Thanks for the reply`s..
Will take a pic today and post..Its situated on the left rear of the boot(trunk)as you open the bootlid.On my car I have the audio amplifier here as well.

I've removed a trailer light and nothing happens..I was under the impression that it would ding and notify the driver via the dash readout ..
Im a funny bugger-if its there it MUST work..no place for passengers..

Barry, do u have the OE horsecock towbar (made by Westfalia)? I have this and the same relay unit you describe positioned beside my amp. It all works when plugged into my car, but the reverse lights on my bootlid stop working when it is. Can't figure out why. The module is in the wiring diagram (see the Bentley manual) and simply intercepts the wiring harness to the left hand light assembly. A new wire leads to the trailer plug- have you the OE plug too?

[Barry]

G,Yes ,the OE horsedong...Im not sure if the plug is OE though as it looks like any of the aftermarket jobs you see.It is mounted beneath the little cover behind the bumper ..
You say your reverse lights stop working??Ok,I can see why,not my idea of what is best,but I can see why..
Does anything else happen-indication on the cluster etc??Imo,if they were as bright as they should have been,BMW would have an indication of blown trailer lights on the instrument cluster..This will obviuosly not be the case as you have said re: intercepting the one taillamp cluster only..

Ive taken the pic but am not sure as to posting it..Is this a Photobucket affair or can I post from my computor directory direct??

[632 Regal]

cant post from your computer direct unless you have an FTP client server, otherwise it has to be hosted somewhere.

[genphreak]

G,Yes ,the OE horsedong...Im not sure if the plug is OE though as it looks like any of the aftermarket jobs you see.It is mounted beneath the little cover behind the bumper.. You say your reverse lights stop working??Ok,I can see why,not my idea of what is best,but I can see why.. Does anything else happen-indication on the cluster etc?? Imo,if they were as bright as they should have been,BMW would have an indication of blown trailer lights on the instrument cluster..This will obviuosly not be the case as you have said re: intercepting the one taillamp cluster only..

I've taken the pic but am not sure as to posting it..Is this a Photobucket affair or can I post from my computor directory direct??

modify your picture to be small (web-size- ie 72dpi and no more than 200dots/pixels high), then you can upload it with your post.

Sorry, to answer your question, the e34 and older e28 have tail-lamp blown alarms for brake and tail lamps (with or without the trailer module). The tow-module allows the standard lamp warning system to work (ie it comes up in your dot-matris display and 'gongs' to alert you when an open-circuit (blown bulb fault) is detected in the system).

If an indicator bulb blows the indicators will flash at double speed to warn you one oif them needs replacment. I am unsure if this covers the trailer also when a trailer module is employed, but the folks at BMW are actually pretty bright

Perhaps I am reading your post incorrectly... how can you see that my reverse lights should not work? Can you suggest why to me? I'd love to fix the damn thing! Thanks in advance, Barry- Nick

[Barry]

AAah,Nick..The plot thickens..
Perhaps we are both interpreting one anothers posts incorrectly..
I read your post to mean that once the trailer electricals are connected,the reverse lights are disabled..by our magical box ,no less..do I have the cat by the balls here??Is this std. working or operation of the system or do you have a fault/problem in the electricals when connecting the trailer which then disables your reverse lights??
If this is the correct operation and not a fault,I can then see (somehow..)that in their thinking the engineers felt it better the reverse lights not work when trailer connected..

On the other hand,if you have a problem ,does this only happen when the trailer electrics are plugged in??Or is this a permanent problem??
In the first instance,I would have to think very carefully about this,if the second,reverse light switch?fuse?open wire?bad connection?my mother in laws curse on me and everything BMW??
Im sure if it were that simple you would have aced it already..

The ding indication of a blown rear bulb or light is a tremendous function on our cars as you say..Im hoping this trailer module extends it to the actual trailer lights as well..Now there would be a bonus..
Do you perhaps know what this module does or is supposed to do??


Thanks Jeff..Will photobucket soon..

[genphreak]

AAah,Nick..The plot thickens.. The ding indication of a blown rear bulb or light is a tremendous function on our cars as you say..Im hoping this trailer module extends it to the actual trailer lights as well..Now there would be a bonus.. Do you perhaps know what this module does or is supposed to do??

Barry, this module:

- switches the trailer lights (additional relays for larger load)
- protects the car circuitry
- extends the ding function

should wire straight in... problem I have with the reverse lights is a weird one. I am yet to disassemble my bootlid wiring harness under the parcel shelf which is where I suspect I have a problem...

I don't think BMW would have disabled the reverses at any point. No reason to do so and it risks compliance problems. Also, when i say it disables the reverse lights on my car; this is when there is a trailer present or not.

BTW the OE connector is an older round type with a well-fitted spring loaded cover on a simple plate beside, right the horsecock. There is a special bumper cutout that covers the whole lot fitted when ordered at the dealer. When retrofitting, one needs the original bumper (or you have to cut yours up a bit), the loom, module, locking key (for the horsecock) chassis to towbar bolts (hardened) and the bumper mounts. You have to drill and seal 4-8 holes for body bolts (use M8 nyloc nuts) behind the bumpers. Simply remove the bumpers and bumper mounts and away you go. (JIC you or anyone else reading might need to know this). Do a forum search on horsecock to find out more...

Nick