928ntslow

Did a search and found nothing to help me. My 82 Euro AT's back up lights are not working. Bulbs are fine, fuse is fine, wiring looks fine.

I looked for the switch on the tranny and couldn't locate where it actually is. I see a multi pin connector at the selector lever. Is it all one unit?

AO

Try putting it in reverse...

Randy V

From the on-line PET (posted in the New Visitor...FAQ topic):

https://techinfo.porsche.com/techinf...82_KATALOG.pdf

Select your model year 78 - 82.

Open> Main Group 3: Transmission

Click> 308: replacement transmission, transmission case AT

Scroll down to:

Illustration 308-05
Item 29 (switch)


The swith is located on the left (driver's side) of the transmission case.

atb

Must be the driver.

shmark

My connector just broke at the switch, one pin separated from the wire and the second was just plain wrong - jury-rigged from somewhere in the dark past. I ordered a new harness from 928sp. Should be a really easy fix, and relatively cheap considering.

Jim bailey - 928 International

Correct the neutral safety switch( on the selector lever ) is also the backup light switch. Mercedes part

928ntslow

Alright you clowns, payback blows.

Thanks Randy, I have PET on my computer here.

Thanks for confirming Jim. I expect that you would have stated these things rarely go out if that were the case, so I am reading between the lines that it's time for a new one.

Now, my brake lights decided to stop working..off to the VW supplier for a couple of switches ....after the Mercedes supplier


BTW, is there anyway to pull the switch and check if it is good or not?

928ntslow

I thought I would follow up on this thread just in case some poor sole like me needs an answer someday.

FWIW, I fixed the brake lights by adding a fuse. Laugh all you want, but I followed the relay fuse chart which is incorrect showing #10 as the brake light location when it is actually #7. My light control unit is just fine.

Now, the back up lights. I did the point to point test with a multi meter starting at the fuse panel. I had 12v all the way to the switch, so there was my definitive answer.

I pulled off the switch by dropping the exhaust (for the unteenth time ) two 8mm head bolts to remove after removing the shifter lever and prying it off. Took it to the work bench and cleaned it off.

Should have taken pictures, but it is rather easy to explain. 4 pin plug that just routes through 2 pins for the neutral safety switch and 2 pins for the back up lights. Threw a multi meter on both and was looking to see if there was any resistance on either loop. Well, yes there was! The only way to see what the problem was by opening the switch. I drilled out the 5 or 6 rivets and opened it up. It works rather easy. There is a cam inside that moves in relation to the shifting of the selector lever (obviously). What is important is that when in neutral, the position the cam is in creates a contact between to points....much like the points in an old distributer. When turned a bit these points open breaking the circuit and then the lobe contacted the next pair of points that complete the circuit for the backup lights. I cleaned both contacts and found that this helped the neutral safety, but not the back up circuit. I had to take a pair of needle nose and bed the bottom contact up some so that it would make contact when the lobe was in that position. A couple of times adjusting and checking continuity with a multi meter and both switches worked perfect.

I put it back together with screws and nuts in place of the rivets, tightened then used a dremel to shear the extra screw length flush with the nuts. Make sure the cam still moves as you put it back together. I had applied some grease to various pivot and turning points to insure proper movement.

Re installed and Bingo, back up lights!!!

Saved a bit of cash on an easy to fix Mercedes switch in about an hours time. Now that you know what to do..I would say it's a 30 minute job if that.

michael j wright

Good job Keith, anyone can replace a broken part, it takes a real mechanic to fix it!

928ntslow

I have spent a lot of money over the years on 928's and have decided that since I already have one that is absolutely "puss", I can cheap out on this one. I have actually been taking a lot of things apart on this car that didn't work and fixed them.

I figure if it is already trashed, no way am I going to hurt it if I take it apart to see how it works. Fortunately I have been able to fix several items.

Thanks

6mil928

I totally agree. A lot of the time these parts can be fixed instead of replaced. I just resoldered my hi/lo beam relay. The headlights kept going out when I hit a bump. I tapped on the relay and they came back on. Works like a champ and saved me $$$. I love easy fixes One of the problems I also have to tackle is my neutral safety switch isn't supplying the ground to the relay and my reverse lights also don't work. I've got the relay jumpered right now to drive the car. After reading your post it makes me wonder if this switch may be part of the problem. Can you see the switch without tearing the exhaust and shifter out?

928ntslow

On my 82 you can. It just makes it easy to remove. I could probably do the whole job in less than 30 minutes now.

Check your current flow to the terminal connection in the spare wheel well. I forget which colors the wires are at the moment, but the pins are 80 and 80a and 50 and 50a (?). It is a 4 pin connector. It comes from the fuse panel and after the connector runs down to the neutral safety switch and back.You can check current to the connector then make a jumper to the corresponding pin on the other side of the connector. The pin right next to it should have current flow if the car is in Park....or the other pins when the car is in Reverse. No current and it is the switch. Just make sure the key is in the #2 position when checking.

6mil928

Thanks for the info I'll check it hopefully this weekend.