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-   -   02 SC2 Intermittent reverse lights (http://www.saturnfans.com/forums/showthread.php?t=267822)

billr 12-05-2020 01:35 PM

Re: 02 SC2 Intermittent reverse lights
 
Can you retrieve the old one and cut it open, so we can get a better handle on how it is designed and how much could be trimmed off?

mistahsnowman 12-07-2020 07:15 PM

Re: 02 SC2 Intermittent reverse lights
 
I checked both the old and new switches on the car today. Both reliably gave continuity, but only with the ball pressed pretty much as far as it would travel. I double-checked them on the vehicle and they did turn the reverse lights on (and remained on), but again only with the ball pressed to the limit of its travel. Seems like the issue here is definitely wear in the transmission, not my switch going bad.

So much for a 10-minute job haha.

billr 02-12-2021 11:11 PM

Re: 02 SC2 Intermittent reverse lights
 
The OP is getting ready to send me the switches to trim down, try to get more reliable operation. Does anybody have good photos of the inside of the shift tower? I would like to see what the mechanism is that actually presses on the switch plunger.

Waiex191 02-13-2021 01:46 AM

Re: 02 SC2 Intermittent reverse lights
 
[url]http://www.saturnfans.com/forums/showpost.php?p=2272399&postcount=70[/url]

[url]http://www.saturnfans.com/forums/showthread.php?t=230898&page=9[/url]

If I have time I'll get a picture from my spare transmission tomorrow.

billr 02-13-2021 01:42 PM

Re: 02 SC2 Intermittent reverse lights
 
Yes, if you can get a picture or two of what actuates the switch plunger it will help me help the OP; come up with a reliable "fix" for this issue. Thanks.

Waiex191 02-14-2021 01:21 AM

Re: 02 SC2 Intermittent reverse lights
 
So it is all in the shift tower. Here is video 1:
[url]https://youtu.be/gVPggnt4udk[/url]

And here is video 2.
[url]https://youtu.be/GCUy7JRNQXI[/url]

fetchitfido 02-14-2021 10:16 AM

Re: 02 SC2 Intermittent reverse lights
 
Well, that's an easy enough fix. Just tear down the tower, put a couple weld beads on the shifter arm and put it back together. Simple, just like those 30yr old 1000pc puzzles from an estate sale :dazed:

Wonder if there's a easy/simple way to get the switch to sit lower/push further into the transmission? Even if you took off a bit too much on the tower surface you could use washers to move it back out.

Waiex191 02-14-2021 10:50 AM

Re: 02 SC2 Intermittent reverse lights
 
[QUOTE=fetchitfido;2357001]
Wonder if there's a easy/simple way to get the switch to sit lower/push further into the transmission? Even if you took off a bit too much on the tower surface you could use washers to move it back out.[/QUOTE]
A milling machine would make short work of it. Otherwise maybe chuck up an end mill in a drill press.

I could not see any wear on the part that pushes the switch. I didn't have the best visibility through the hole.

billr 02-14-2021 03:13 PM

Re: 02 SC2 Intermittent reverse lights
 
Thanks, that is exactly what I was wanting to see. I/we will keep you advised if I can come up with an easy mod to the switch to make it more reliable.

billr 03-07-2021 12:10 AM

Re: 02 SC2 Intermittent reverse lights
 
It is time to revive/update this thread:

The OP sent me two switches, one used and one new. I have set the old one up with a dial-indicator to check operating points and have some preliminary results. Total travel is .100", trip point is .040", and reset point is .045"

You read that right (and no typo), the hysteresis seems to be [I]negative[/I]!

Obviously, I need to thoroughly check my setup and procedure tomorrow, with fresh eyes; and check the new switch. Stay tuned...

billr 03-07-2021 07:30 PM

Re: 02 SC2 Intermittent reverse lights
 
Well, I did more testing today on both switches.

The total travel is the same on both, .115" This is travel of the ball/plunger from its free position until it is flush with the end face of the male thread. the old one will go in further than that face only slightly (.010"?), but the new one will go in quite a ways (.060"?). I thing that "extra" travel is irrelevant, though, because I don't think the cam in the trans can poke the ball in past the end of the male thread on the switch.

Both switches are .415" from the face under the hex that tightens against the trans case to the tip of the ball at free position.

Both switches have a very narrow hysteresis/dead-band between on/off. It seems to be only a few thousandths (<.005") for both.

The big difference is in where that off/on trip point is. For the old switch it is .050", but for the new switch it is .095" That .095" is so close to the max travel available (.115") that I feel the new switch is unusable! Frankly, I think the switch design is marginal, a short travel like that is too finicky for an application like this, but at least the old switch with trip at mid-travel has a chance.

There is no noticeable tactile or audible actuation of either switch. I'm thinking they are reeds with a magnet to actuate. Again, too dainty for an app like this.

Questions for the OP:
I would like to take one apart to see how they are constructed. Do the new one which is poor anyway?

If I can't sacrifice one, then I can mill a tiny window in one to get an idea how much can be trimmed off under the hex. I don't think that window will affect operation of the switch, and if it ruins the "water seal" of the switch, I think that can be restored well enough with a dab of RTV or JB Weld. Go for it? Which one?

Suggestions from anybody else?

Signmaster 03-07-2021 07:45 PM

Re: 02 SC2 Intermittent reverse lights
 
With a design like that, it's a wonder they worked at all. I thought there was more travel than that. It sounds like the new switch is more or less done out of the box.

billr 03-11-2021 10:40 PM

Re: 02 SC2 Intermittent reverse lights
 
I got the OP's permission to cut the new one open. It is a pretty crude design!

That end surface that I could trim is .160" thick, so I think I could take .080" off the old one and it could still be tightened properly. Of course, that is assuming the old one is constructed nearly the same...

Does anybody care about seeing the innards of this beast? I am poor at taking/resizing/uploading pictures, it is a fairly tedious process for me, but I will do if anybody wants.

Waiex191 03-12-2021 09:46 AM

Re: 02 SC2 Intermittent reverse lights
 
I'm always interested to see pictures. What platforms do you use? Windows, apple, desktop, phone? Maybe this is a great time to get help from one of your forum mates and learn a new skill.

billr 03-12-2021 12:00 PM

Re: 02 SC2 Intermittent reverse lights
 
I use Win8 with Chrome. I take pix with a camera, then transfer by moving the SD card to laptop. After that I bring it into Win Paint to re-size and get small enough to post. I can [I]do[/I] it, but not as simple as I would like... Will do later today.

My plan is to trim .060" off and return all to OP, but I would like to hear from OP again to see if he agrees.

Waiex191 03-12-2021 12:30 PM

Re: 02 SC2 Intermittent reverse lights
 
billr,
My favorite is irfanview. You can get it for free here:
[url]https://www.irfanview.com/[/url]

They have a resize thing, basically hit ctrl-R and you can can basically keep halving it in size until you are happy. Or you can type in the size you want.

It is super easy to use and also works great for looking at pictures on your PC.

billr 03-12-2021 04:54 PM

Re: 02 SC2 Intermittent reverse lights
 
I downloaded and used that program for the attached picture. It doesn't seem to be much different (or easier to use) than Paint, but I will give it a few more tries.

The ball pushes on that brass assembly, the assembly being two rivets that telescope inward compressing the little spring. This assembly provides the over-travel for the switch.

The brass pushes on the blue rubber disk, the disk acting as an electrical insulator and a seal to keep trans fluid from getting into the contact area.

The blue disk pushes on that (aluminum) cup and forces it against the big spring until the cup touches the two contacts that are merely the inboard end of the connector sockets.

It is no wonder that there is little-to-no hysteresis. As to why the trip point is so far in, I can only guess. The big bore in the metal housing looks to be drilled, not the most accurate way to control depth. And the brass "rivet" assembly may have loose tolerance. I would expect the molded connector housing, ball, cup thickeness, and rubber disk thickness to be quite accurate. Or, maybe the aftermarket vendor for this part just copied it poorly!

Waiex191 03-12-2021 04:58 PM

Re: 02 SC2 Intermittent reverse lights
 
I wonder if there is a better limit switch that could be adapted to the shift tower.

I didn't see any attachment in the prior post.

billr 03-12-2021 06:59 PM

Re: 02 SC2 Intermittent reverse lights
 
1 Attachment(s)
One of my failings is that by the time I type a reply, I have forgotten to attach what I am describing!

mistahsnowman 04-06-2021 12:15 PM

Re: 02 SC2 Intermittent reverse lights
 
I got the trimmed switch back from Billr yesterday in the mail and put it back in the SC2 this morning. It seems to work well - no flickering. Every time I put the car in reverse, the light comes on steady and consistently. So I'm going to call it a success.

Thanks again to everybody for all your help/suggestions and thanks especially to Billr for volunteering all his time and effort in studying the innards of the switch so we could discover a solution.

Hopefully this thread will help anybody else currently with this issue or anybody who runs into it in the future!


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