Always "in" reverse

[dscoff]

I'd exhausted my search and self diagnostic avenues regarding this issue, so a post was the next step.
My '02 3.0 X5 with manual trans constantly thinks it's in reverse; that is the reverse lamps are always on and with the passenger side mirror is always tilted down (if the selector switch is in the correct position).
The reverse lamp switch is fine; I've tested it with a multimeter, tried a second one and tested it with a multimeter while installed (to make sure the selector rod was actually activating the switch.
The lamps etc stay on even with the switch disconnected, but there doesn't seem to be a short in the harness. I checked the resistance between the two sides of the plug and it's infinite (no connection/short).
Pretty sure it's a LIM issue at this point which probably requires the GT1. Just wanted to fish for some answers before shelling out money at a shop or for a GT1 of my own.
Thanks!
Jonathan

[Bulk]

The reverse switch closes the circuit so with the switch removed completely there is no logical reason to why the lights stay on.

Do they go out when the car is off? or in position 1?

[dscoff]

I know! The only non-LIM reason I could think of was a short in the wiring, but I tested it for continuity (one multi-meter lead on one prong of the plug, the second on the other prong, resistance was 1 (infinite)).
The parking-mirror tilt is the other give away... it's not just a lamp issue, the truck "thinks" it in reverse (unless the mirror cues of current flowing in the lamp circuit).
They go out and the mirror returns to it's normal position when the vehicle is off or in position 1.

[Bulk]

Have you tried disconnecting the switch electrically at the tranny? I know you've tried other switches an all that but have you just unplugged it and seen if it still does it?

[dscoff]

Yes, that was the switch to which I was referring. To be clear, the lamps are lit (and mirror tilted) with the plug that connects to the physical reverse switch (threaded into the trans) disconnected.

[stock545i]

Originally Posted by dscoff

Yes, that was the switch to which I was referring. To be clear, the lamps are lit (and mirror tilted) with the plug that connects to the physical reverse switch (threaded into the trans) disconnected.

I would think it's the switch/sensor on the transmission. Maybe disconnecting has same effect as being stuck in reverse?


I found this on another BMW forum:

My reverse light and mirrior would dip in any gear. Frist I thought it was the back up light switch and replaced it. Didn't do a thing. The way I fixed it was easy. The gear identification switch has a wire connected to it. That same wire splits in two and plug into a sensor that is a little forward of the gear identification switch. I just switched the two wires, somehow the wires were disconnected and someone put them on in reverse. problem solved..
GL

[Bulk]

Originally Posted by stock545i

I would think it's the switch/sensor on the transmission. Maybe disconnecting has same effect as being stuck in reverse?

That's a good point 545. Did you try shorting the plug that connects to sensor with a paper clip or something and see if that fixes it?

[Bulk]

Well I have been zero help. I'm stumped. Maybe one of your Lighting Modules has gone (A3 maybe).

Sorry

[dscoff]

I believe he (she)'s referring to an automatic transmission, as the manual doesn't have a gear identification sensor or switch.
The only wiring, switches or sensors on this trans is the single, mechanically activated reverse lamp switch. It's almost identical to the one on my '69 2002: just a push button switch that is "pushed" by the reverse selector rod inside the trans and opens or closes a circuit. Disconnecting this switch would have the same effect as being out of reverse, as the circuit would be open. As previously mentioned, this has no effect, so I'm thinking it's a lighting module.
Thanks for the interest and the search though! Keep coming with more ideas!
Jono

[Bulk]

maybe they've wired it to be in reverse as in selecting reverse breaks the circuit? Hence shorting the plug would confirm or deny the theory......