No reverse lights? Elec is fine - how to test the switch actuator?

[cirrusblue]

Hello R3V,

I posted in a more select category but didn't get any eyes and this is a little general because it's about testing a non working function...

Basically, my drivetrain ripped out my reverse light wires in my 87 325e. At the same time, there was funny tapping only when I was in neutral and I can't really figure out what happened. Suffice it to say that now that I've put it all back together when I put the car into reverse - the lights do not go on.

The switch is good, the electrical is good - I can remove the switch, depress it and the ligths come on.

My indy says something let go in the tranny. I look for days in Bentley and real oem at transmission diagrams and can't figure out for the life of me what actually depresses the switch. Secondly, I'm racking my brain how to even test the reverse "actuator" is working and how I can do that while on a lift or jacked off the ground.

Any ideas how I'd try to debug why the switch isn't being pressed?
I bought a few extra switches considering re-fabbing a switch with a longer plunger. Also, I've read threads from other manu's about a rod that I don't really think this car has.

I have the getrag 5 speed.

If any sympathtic soul who's experienced has a suggestion how I'd approach this I'd really appreciate it. I can't pass inspection and the car is mint otherwise!

- CB

[Todd Black 88]

Hello R3V,

I posted in a more select category but didn't get any eyes and this is a little general because it's about testing a non working function...

Basically, my drivetrain ripped out my reverse light wires in my 87 325e. At the same time, there was funny tapping only when I was in neutral and I can't really figure out what happened. Suffice it to say that now that I've put it all back together when I put the car into reverse - the lights do not go on.

The switch is good, the electrical is good - I can remove the switch, depress it and the ligths come on.

My indy says something let go in the tranny. I look for days in Bentley and real oem at transmission diagrams and can't figure out for the life of me what actually depresses the switch. Secondly, I'm racking my brain how to even test the reverse "actuator" is working and how I can do that while on a lift or jacked off the ground.

Any ideas how I'd try to debug why the switch isn't being pressed?
I bought a few extra switches considering re-fabbing a switch with a longer plunger. Also, I've read threads from other manu's about a rod that I don't really think this car has.

I have the getrag 5 speed.

If any sympathtic soul who's experienced has a suggestion how I'd approach this I'd really appreciate it. I can't pass inspection and the car is mint otherwise!

- CB

There is a dimple in the reverse selector shaft in the tranny that the switch rides in. When you put the car in reverse, the shaft moves backwards and he switch rides up the dimple and depresses.

I had to make my switch longer also.

[cirrusblue]

Todd - would you share how you lengthened the switch plunger? I have a few switches, dremel, jbweld, solder equip etc. Considering the best way. I'm going to take one apart and take a look at it.

Sent from my XT1528 using Tapatalk

[Todd Black 88]

http://s14net.vbulletin.net/forum/s14/general-e30-m3-discussion/11454-reverse-light-connection-on-tranny/page3

[cirrusblue]

That's awesome. Thank you so much.

[cirrusblue]

That's awesome. Thank you so much.

I just made a couple new switches that are longer so fingers crossed.

Sent from my XT1528 using Tapatalk

[Todd Black 88]

Good luck

[///M42 sport]

touch the connector wires together

[McGyver]

Sorta like he^ said:

Test the circuit by touching the wires together, you should get lights if you connect the bare metal.

Test the switch by using a multi-meter to test for continuity when you have your car in reverse.

[Todd Black 88]

Guys, read the op.

He has done all that. The circuit works, it's an actuation issue in the tranny.

[McGyver]

Guys, read the op.

He has done all that. The circuit works, it's an actuation issue in the tranny.

It had too many word in it.

[Todd Black 88]

It had too many word in it.

Lol

[cirrusblue]

It's working!

Hey, thanks for the help everyone.

It's working!

I built a few switches by cutting up some FAE switches and making them in various lengths. I cut the top off of one, flattened and drilled the top off a comlete switch, put a little metal rod in the middle to support it and then JBwelded the top on to the switch. then dremeled it flat and smooth.

overall came out great and the first one I put in worked like a charm - abou 1/8th inch longer. Good news is it's working and no expenseive tranny bs.

thanks for the help! your post gave me the help I needed to try it out.

[Todd Black 88]

Glad it worked out!

Same issue I had.