What can go wrong with backup lights? Mine stopped working last year and I can't seem to figure out what's wrong with them. I replaced the neutral safety switch and both bulbs, but that didn't do anything. One of the sockets was a little corroded, but I cleaned it up and they still don't work. Can anyone explain how they get their power? How do you test them if they only work with the car running and in reverse? Any ideas would be appreciated.

Sorry, im not the best when it comes to wiring, but maybe back in the trunk, clean off any and all areas where the harness gets grounded. maybe there is a part of the wiring that the insulation has worn through and is grounding it.

Have you checked them to see if they are getting power in R?

wish i could help more.

-Mike

Do you own a test light? If not get one! First test, key on engine off, unplug the three wire connector at the neutral safety switch & check for power on either of the outer wires...If you have power try putting a jumper from that wire to the other outside wire...then check the lights...If you don't have power check your fuses...If you have power but the lights don't come on with the jumper, leave the jumper in place & test for power at the B/U light sockets...if you have power either you have bad bulbs or a ground problem...No power? Check for power at the connector behind the drivers kickpanel...If no power there check the bulkhead connector... Maybe there's a reason some guys don't like electrical problems...

I'll check for bare wires. That's always a possibliltiy with an older car. Where are they grounded? My brake, parking lights and turn signals work, so I figured the ground was good. Can you check them in reverse with the car off and the key in the on position? I thought the car had to be running for them to work. Not sure on that though.

Now that gives me some things to try! Thanks! I do have a test light, so I'll give it a shot.

Your shift linkage could be off a little. It doesn't take much. Have you tried moving the shifter around to see if they blink on at all?

And lastly, the aftermarket safty switch center pin is usually too long...This center pin drops into a detent in the "rooster comb" that actuates the back up lights....You may need to file the center pin so it bottoms in the switch completing the circuit....

Or put the correct washer under it.

You guys may be on to something here. My backup lights stopped working around the time I replaced my neutral safety switch. I replaced the switch because it wouldn't always start in park or neutral, not because my backup lights weren't working. So the middle pin is too long? What does filing it down do? Does it allow the plastic wiring harness plug to go on the switch more? This is probably why I've been banging my head against a wall with this problem. I'll give it a shot tomorrow if the weather's decent. Thanks for the idea!

Or are you talking about the movable pin on the switch in the plastic plunger that goes in the tranny? How will filing that help? I'm sorry, but I don't understand how this stupid pin works to complete the circuit. Boy, do I hate electrical problems!

I'm going off memory but the pin is for starter operation in neutral/park, the pin is attached to the center wire which goes to the starter relay & supplies the ground to the control side of the relay, when the metal selector lever touches the pin it supplies ground...the two outer wires are for reverse & have conituity when the plastic plunger is depressed...

Okay ,we're talking about the BOTTOM of the switch with the plastic plunger and the small center, metal pin... ... The neutral safty is operated by the big plastic plunger on the switch.. .For park and neutral this plastic piece drops into a recess in the "rooster comb"{this feature is basically a ground}.....For reverse, the recess in the comb is smaller...So the plastic neutral safty plunger just rides along the comb, but does not drop...But the small steel pin does drop into the hole, bottoming the steel pin in the plastic plunger case and completing the circuit for the back-up lights{the two outer wires on the switch}..
..So what happens when the pin is too long is:....When the pin drops into the recess, it doe'snt extend the full travel and can't bottom out in the plastic plunger because the pin itself is too long....filing the pin will allow it to bottom completely in the plastic neutral housing when in the rooster comb reverse detent{recess} and complete the circuit...

Here's what to try to see if you're on the right track....Take out the saftey switch from the transmission and hook up your wiring harness....You should have back up lights, if you don't , there's something else wrong{faulty switch or wiring problems}..To check for a faulty switch, run a jumper between the two outer wires on your back-up/ safty switch harness..If you have lights, the switch is bad....If still no lights you have a wiring problem ... . Now,assuming you have reverse lights... If you push the center pin in by itself the reverse lights will go off....It does'nt matter where in its travel the plastic neutral safty plunger is...All the way in or out or anywhere in the middle, if the pin is extended, the lights are on because ...the pin only has the opportunity to extend{by itself} out of the plastic plunger in the reverse recess on the rooster comb...
Does this make it any clearer on what COULD be the problem ???

screamindriver, YOU'RE THE MAN! Thanks to 1 WILD RT's detailed troubleshooting instructions, I got the backup lights to work with the jumper on my neutral safety plug. I took the switch out and shaved a bit off the pin and now my backup lights work! I can't believe the pinheads who make this switch would make the pin too long. You have no idea how many hours I've spent trying to fix this problem. I just assumed the switch I bought was good, because it solved my neutral safety problem. Now maybe I can get my elusive inspection sticker so the cops will leave me alone. Thanks again to everyone who helped me with this incredibly annoying problem!

Glad to help !There were some great troubleshooting tips that covered everything related to this problem... This time it was an easy fix if you know what to look for...It took me a while troubleshooting the first aftermarket piece to see what the problem was....Have fun driving your car !!

BTT - this just saved me a trip back to the parts store to get another defective switch.

Now can someone tell me where to get a pigtail for the backup light/NSS switch? I tried the local parts stores, no dice.