Have 88 with a 4+3 Doug Nash trans, just installed a rebuilt overdrive unit in it and can't seem to figure out why my back up lights won't come on in reverse. but they do come on in the other gears.
The ball sensor switch seems to be reversed as to when it comes on and when it should go off.
I'm fairly certain I have the correct switch or do I ?

 

I'd say maybe NOT - 14057528 (B/U) (GRAY), 14057529 (O/D)(BLACK) - Do you have GRAY and BLACK switches? I'm not sure that they were always colored differently but GM did little things like that for assembly purposes. GM also indexed/colored the Weather-Packs differently that connected them. I'd confirm all of the wire colors and check the switch colors maybe. I'm assuming you've the FSM.

Under what circumstances do the lights actually work? Which gear is selected and is it in OD or NOT?

 

Yes I do have the FSM and thats where I got the part number from bought it on ebay as they are hard to find. Yes it is gray and the problem was the box number the part came in was unreadable so I had to tak the sellers word on the part number.
The black one is a smaller diameter so you can't make a mistake there also the plugs are not inner changeable. I will get back to you on when it does come on.
Thanks

 

Do you have your old switch? You can check the operation of it on the bench. The B/U shouldn't have required an eBay buy. "LOCAL" - I would have thought. If you were supplied an incorrect switch that has opposite control that could certainly explain the "ON" in other gears. What's on the box of what you bought?

Maybe soak your old switch and exercise the depressed ball, that type of switch getting used seldom can certainly find itself "stuck". I'd think the switch should be N/O so depressing the ball should close and activate B/U lights. You might see if there's maybe a NAPA NS6599 available or maybe a Standard LS351 from Carquest or similar. Those I believe are N/O and be correct. You would need to confirm operation. I've a friend who whenever using a "depressed ball" operated switch confirms on a bench before installing. He taught me to do likewise. Some are very difficult to reach and the "second time" is never a joy.

If I were needing I'd be looking for a Wells SW8201- it displays all the correct specs and on their print it gives thread specs and N/O (It also has an OE/GM reference on their print)

http://www.wellsve.com/custom_search...ngs/SW8201.pdf

 

I checked it today I have the car on a potable type hoist. The backup lights are on in all gears. If I remove the switch and depress the ball by hand, they go out so the switch must be wrong and not going in deep enough?
I ordered a Standard Parts LS 351 today so maybe that will be different . Thats the number my auto parts store says it takes.
I will let you know.

 

Unfortunately my old one was broken and it does nothing.
Just so happens went to my auto parts store and ordered a LS351, so we'll see what happens.

As I said above the car is in my garage and is up on my portable hoist so it's not so bad to get to and I intend to leave it there until I figure this out.
I will check out wells thanks for the info !

 

I doubt if it's a "deep enough" problem - the fact that it works "BACKWARDS" (B/U on in all forward gears) in your hand confirms I'd think that it's a N/C switch instead of a N/O. Compare your LS351 to the Wells print.

 

Hey thanks the LS 351 is correct and works now. however I did grind the base down slightly so the switch ball would make good contact.