Re: Backup light / 1-4 issue
 

Well, it's just a tad bit smaller sized than the bore diameter. So there's not much room for it to actually move, no place to go. I hope...

For sure it's better to grind down the mating surface of the switch to get it deeper down the hole. But as long as I don't know where the root cause lies I rather not make any mechanical changes but take a reversible interim solution to gain some time

Re: Backup light / 1-4 issue
 

For over twenty years it has been the switch, as they have routinely failed.
While the possibility exists that it could be more, the probability remains high that it is just the switch.
Let us know what happens once it has been replaced, and if needed, we can go from there.
Best wishes for a simple solution!
:cheers:
Marty

Re: Backup light / 1-4 issue
 

I agree with Marty, it seems improbable that your transmission has developed a fault that does not appear common, whereas the switch being defective is quite common.

One way of harmonizing both views is to reflect on the fact that we don't really know what the functional specification was in the first place, for how much deflection was needed to activate the switch. Perhaps GM and/or ZF specified a very small deflection to activate the switch, whereas over time the switches become less and less sensitive needing more deflection to activate. So when you're bench testing your switch, you're pressing down enough to activate it, while a new switch would be much more sensitive and capable of switching on the reverse lights with just a tiny input from the transmission. This is all just conjecture, of course, but as I said maybe a way to see how both "facts" would align.

Re: Backup light / 1-4 issue
 

Hm, very good point. Maybe the required travel is really THAT small... The new switch is on it's way anyway, unfortunately takes ages to arrive here. So for my second attempt to get her certified next week I'll have to go with the interim solution. But as soon as the switch arrives I will try it.
Most probably you are right.

Re: Backup light / 1-4 issue
 

Wise man! Never thought about that point. And it scares me when I do.

I received a notification that the switch will be delivered tomorrow. Let's pray it will happen as on Wednesday I have my federal inspection and definitely would appreciate to NOT install any work around just for that (no backup light -> no registration). Also then we'll have the answer: German angst or a real mechanical issue :D

Re: Backup light / 1-4 issue
 

Reminds me of local news when I lived in Florida. A guy tried to steal gas from a camper during the night but had the hose in a wrong tank and tried to siphone using his mouth. Quite a surprise.:)

Re: Backup light / 1-4 issue
 

I guess, oh sh!t went through his head...

Sorry, multiple puns! :)

Re: Backup light / 1-4 issue
 

Interesting, I have a 94 and my backup light does not work and I do not have any skip shift functions either, so no matter how I drive I am able to go thru all the gears. Rarely do I have it out at night and even rarer would I use reverse at night, so it hasnt bothered me enough to try and fix it.

Re: Backup light / 1-4 issue
 

We will be changing out my backup light switch this Sunday at our Wazoo maintenance day in Westminster. Come on over.

Re: Backup light / 1-4 issue
 

A possibility!!!! Pretty close by in Reisterstown. Thanks for reminding me.