72 cutlass S
automatic th400
column shift

ok, so I just about have all the lights working except the drivers side back up light and the light over the license plate.
I swapped out neutral safety switches and the replacement behaved the same way as original one. Meaning if i rotated switch to the right I can get atlest the passenger side light to come on.
I am running out of options here before I just replace the harness in the steering column. I really do not know what else to do.
I am going to try to figure out how to use my volt ohm meter in the meantime.

fuel gauge does work, blinkers, head lights and turn signals.hazard lights work as well.

what do you think?

 

If one side of the backup lights work correctly it's not the switch. Also remember adjusting the backup light switch will also affect the neutral safety switch. The license plate light is not on the same circuit as the backup lights, different issue.

 

Check grounds on the lights that don't work. 50 years of dirt and corrosion can make them not work. That was the problem for me on my 71 back up lights.

 

Good advice from Larry. Most likely culprit is a bad ground. Take the mounting screws out and clean up the mounting area and put it back together with the screws good and tight. It will probably work.

 

thanks for info! I found what looks to be a ground screwed into trunk lid receiver in trunk. looking for grounds!

 

forgot to mention license plate light works after new bulb

 

I had trouble with the back-up lights not working on my '69 4-4-2. Checked the bulbs and they were good. But it seemed the metal surface on the bulbs and/or the tabs on the metal surface weren't making good contact with the metal in the light socket. I cleaned out the area where the tabs lock into the socket and that made all the difference in the world. The back-up lights work now.

Randy C.

 

The ground screw in the trunk is for the side marker lights in the quarter panels. There is a seperate connector for each reverse light that plugs into the harness in the trunk. Use a test light to check the connectors. To rule out a ground issue, Use a test light attached to positive and touch it to the bulb housing with the lens off and the bulb out.

 

Thanks again for additional tips.

What i have done so far.

I disconnected right bu light and plugged the direct line from left backup light into the power feed(from the harness) from working right backup light and nothing happened. even thoough when I plug the right light into the right power feed the light works. So i guess perhaps the left bu light may need more work in cleaning socket out or replaced. or I need to find another ground somewhere??

I also tested both feeds to the backup lights when lights were disconnected and both show 13.125v on voltmeter when car is in reverse.

When I tried other backup light housings I have they dont work either. I tried plugging them into both the right and left backup light power feeds. I even tried to get the spare housings to work by jumping on main battery and nothing happened.

 

Did you connect a ground to your spare housings?

 

no i did not connect a ground to spare housings.ill have to make one.

Update:
I removed housing and cleaned up where it bolts together. nothing changed.
I just pulled plug(with 2 shades of green wires)off neutral safety switch and used a little piece of wire to connect both feeds in plug and same thing happened, only the right passenger side backup light came on.
I tested fuse, both sides getting 13 volts.
i tested plug that i removed from neutral safety switch an only the one side was reading 13 volts, the other side was dead.

Im thinking I might have to replace the harness in column. so close to not having to do that. Everything else light wise is working.i looked at the harness i bought for inside column and those connectors that control the rear lights are not there. so maybe it isnt the harness in the column.

 

Again, if one of the lights is lighting, there is nothing wrong with the fuse or wiring going back to the trunk. If you're getting 13v at both light sockets, the one that is inop is missing the ground side of the circuit.

 

just another update.
so had wife put car in reverse. tested both feed, getting 13.1 volts per lead to each bu light.
jiggled non working light and it would come on. must be in housing for bulb! getting closer!

 

thank you sir!

 

Kind of a rinky-dink solution for the looseness between the housing and the bulb, but try a small piece of tin foil to see if it solves the problem. It sounds like the problem is the conductivity between the metal side of the bulb and the bulb housing.

Randy C.

 

I installed a used replacement housing and walla! Should have started there but learned a lot going through everything.

it works! I am good to go all lights now working.

 

Well done.

 

Some of the best money you'll ever spend... get some CRC contact cleaner and some dielectric grease and a lot of electrical aggravation will fade into the past.

 

LOL! Yes sir I agree. This was my dads car he left parked in his moms garage since 83 and he loved to use the dielectric grease so it was real fun to clean it up after if turned brown and gunky LOL. I should still get some though since car is runing again---- great freekin tip!!

 

That sounds more like white grease. I've used it too, but lately I've been using SuperLube which is a synthetic clear grease. Keeps the corrosion away and doesn't turn hard and brown like the white lithium grease does.

I haven't found much the synthetic grease doesn't work well on.