Backup light / 1-4 issue - Page 3 - ZR-1 Net Registry Forums

Matt B · 04-08-2021

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

DRM500RUBYZR-1 · 04-08-2021

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!

Marty

ram_g · 04-09-2021

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.

Matt B · 04-10-2021

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.

Matt B · 04-12-2021

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

secondchance · 04-12-2021

Quote:

Originally Posted by Paul Workman

My grandfather (IIRC) said that if left in REVERSE and someone tried steal it by push starting.... Well, never mind about the rest: that makes 'sense'...I guess!

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.

ram_g · 04-12-2021

Quote:

Originally Posted by secondchance

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.

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

Sorry, multiple puns!

ZR2 · 04-14-2021

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.

dredgeguy · 04-15-2021

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

ZR2 · 04-15-2021

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

04-08-2021	#21
Matt B Join Date: Jan 2021 Location: Beautiful Bavaria Posts: 520	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 __________________ ZR-1 #638/1991

04-08-2021	#22
DRM500RUBYZR-1 Join Date: Sep 2008 Location: Mullica Hill, New Jersey Posts: 2,566	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! Marty

04-09-2021	#23
ram_g Join Date: Jun 2020 Location: Houston, TX Posts: 183	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.

04-10-2021	#24
Matt B Join Date: Jan 2021 Location: Beautiful Bavaria Posts: 520	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. __________________ ZR-1 #638/1991

04-12-2021	#25
Matt B Join Date: Jan 2021 Location: Beautiful Bavaria Posts: 520	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 __________________ ZR-1 #638/1991

04-14-2021	#28
ZR2 Join Date: Jun 2018 Location: Maryland Posts: 53	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.

04-15-2021	#29
dredgeguy Join Date: Aug 2012 Location: Ellicott City, MD Posts: 1,635	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. __________________ Charlie __________ Dredgeguy WAZOO Member 1992 Bright Red/Black ZR1 #246 Dana 4:10 gears Polished LT5 by Haibeck Polished Fikse FM5's with Michelin Pilot Sport 2 Stainless Works headers and cats with Corsa

04-15-2021	#30
ZR2 Join Date: Jun 2018 Location: Maryland Posts: 53	Re: Backup light / 1-4 issue A possibility!!!! Pretty close by in Reisterstown. Thanks for reminding me.