I believe the title says it all. I did a search in the forums for solutions to this problem and i found one but it was in the 5th gen forum and i don't know if it applies here.

I have a 94 Maxima SE DOHC 5-spd. The motor was switched out and transmission had to have a new main bearing put in. When you put the car in reverse neither reverse light comes on. The bulbs aren't bad.
The 5th gen thread said it was a bad switch on the transmission and that you'd have to make a trip to the dealer for one because autozones/napas/advance auto parts don't sell them.

If that still does pertain to me, could someone tell me where this switch is located on the transmission? Thanks

 

Look for the only place there are wires coming out of the tranny. It will be at the bottom on the driver side, if I recall correctly. The are about $16 from rockauto.com

The contacts usually corrode, which causes this to happen. The switch also controls the only-starts-in-neutral function, as well as the cruise control. You will need to drain the gear oil before replacing it.

 

Sounds like your referring to the speed sensor.

 

No its the neutral safety switch its on the drivers side of the transmission and its down the the side almost at the bottom. there are two sets of wires on a manual transmission one is the speed sensor and the other is neutral safety switch. Be prepared to lose all gear fluid once you pull that switch and have a drain pan ready as well as 2 quarts of gear fluid. it takes about 1 and a half quarts of gear fluid to fill the manual transmission back up and you fill it through the speed sensor hole.