back up lights

[oldsnofear]

Hi
on my 69 charger with a 727 trans i replaced the nss and still have no rev lights.  I tried a standard one and a advanced auto one neither work if i jump the 2 outer pins in the pigtail they work. Is there something broke in the trans? I read other posts i dont see how you could shim it? Thanks Shawn

[John_Kunkel]

There is a spring loaded metal plunger in the center of the plastic bushing in the switch, this plunger must extend all the way out to turn on the BU lights.

With the switch on the bench, attach a meter or test light to the two outside prongs of the switch, then depress the plunger to break the circuit and allow it to extend to complete the circuit. If it works OK on the bench but not in the car the plunger might be too long. If the problem is a long plunger you might have to shim the switch.

Also, with the switch removed, look in the hole and make sure the "divot" in the plastic shoe doesn't have an obstruction.

[oldsnofear]

Thank you for the  great pic. the switch works on the bench(the one i took out that didnt work). Can i shave the plunger down a bit? how would i shim it? it has a taper seal on it Thanks again

[oldsnofear]

 Hey just to let you know i got a ac-delco switch and the plunger rod is 1/16 shorter than a standard or bwd switch i installed it and it works great. Thanks  for the help Shawn

[John_Kunkel]

Kinda sad when only GM makes a correct replacement part for a Mopar.