Well I've got everything back together on my 73 Charger. Everything seems to be working except the reverse lamps and I'm not sure if there is suppose to be a buzzing when I just leave the keys in the ignition. The seat belt system was puzzling but turned out to be the simplest thing. After two weeks of tearing apart and checking all the circuits, it turned out to be a sticky driver's side seat belt switch. It wasn't fully retracted. That's it. It works great now. The engine starts up perfect. But no reverse lights. All lights in the rear work. Tail lamps, side markers, license lamp, and brake lights. Does that mean the reverse lamps would have a good ground too? According to the wiring diagram on a WH23 body, it looks like all the wiring for the rear lights is tied into one ground wire at the driver's side of the inner trunk panel. So where do I check first? The other part was something I'm not sure of. This thing has a buzzer that sounds when you leave the key in the ignition and the headlights on, but what about if the headlights aren't on and I leave the key in the ignition. Does anyone know if it should still sound? I'm still confused about that. So I haven't tightened down the steering wheel yet because of that.

quick check, if you have it, is to peek the owners manual, and see if it describes a "key reminder' for a buzzer. it would be in the book, if you have it.

FWIW, the buzzer in my 74 has never worked nor have the reverse lights. I've daily driven the car for 6 years spring-fall and never cared to fix it.

But if you want to check out the reverse lights, try hooking a 12v test light and check to see if power is even getting back there when you put the shifter into reverse. If it's not, check out the reverse switch on the transmission, possibly is shot or not connected.

Easiest way to check wiring and grounds for the back up lights is to disconnect the NSS plug and see if you have power to either outer terminal with the key on. If you do then just jump the two outer terminals on the plug and see if the lights go on. If the do then you either have a bad switch or your linkage is out of adjustment slightly. If the lights don't go on then you have a wiring problem from the switch on to the back.

If I've got power at the fuse for the backup lights when it's in reverse does that mean everything between the fuse block is properly plugged in and not broken? That's what I'm most concerned about. It only starts in Neutral and Park and all gears feel firm when I shift them with the selector. Could it still be out of adjustment then? I replaced the neutral safety switch, and got a new harness from Year One. I'm going to see if I'm getting power back in the trunk harness when it's in reverse. If it's anymore out of adjustment I don't know how to make it any better.

Assuming of course, since the car is 37 years old you checked the bulbs.

The ground on the reverse lights is just the housing. If you look at the plug it is a single wire. You can check for voltage here in reverse. If you have voltage, it is a ground issue.

If I remember correctly the reverse harness is just two wires at the bulkhead, see picture, this is a older RR but should be similar.

It should be plugged into a something and leading to the transmission reverse switch. On this picture it is not.

If it is plugged in, unplug it and jump the two wires together as it is a little easier than crawling under the car. Check to see if the reverse lights are on. If 'on' you most likely have a bad reverse (NSS) switch. If unplugged well you know it is not plugged in and that your problem.

If not on check to see if one of the two wires has 12 volts. If no then the fuse is most likely blown.

If you get battery voltage you have a issue with the wire going to the reverse lights. The white with black tracer before the rear harness plug and violet from the harness plug to the reverse light.

Of course all of these test are done with the ignition switch in the 'on' position.

your buzzer will not work when just the keys are in the ignition...for the buzzer, the ignition has to be on, or the lights have to be on... but keys in, with the ignition off....no buzzer. as for your lights, if you have power to the fuse box, have you tested for power at the reverse light sockets? if you have power, then it has to be a grounding issuee. is the car freshly paitned?

If it only starts in neutral your linkage is still a little out of adjustment. The neutral spot is more forgiving then park. Have you tried jumping the wires at the NSS as I sugested. That is the best way to tell if it's a linkage or switch problem.

even if the adjustment was off, the backup lights should still come on (though maybe not in reverse) as he moved the lever down through the gears...at the point where it hits that contact, the lights would come on. so adjustment should be ok. and if the car doesnt start in gear, you know the switch is ok, then youres back to tracking power and ground.

He never mentioned if he had someone watch the lights while he went through the pattern. I assumed he stuck the shifter in reverse and looked to see if the lights were on.

could be worse,my back up lights come on in reverse and come on and stay on when i shift into drive ,try doing like said with a simple test light car in reverse,key on,check to see if there is any power there,your plate light is in the same harness,does that work?

stumpy youre right, he didnt, i guess i took for granted that they would have done that, lol. didnt mean to step on toes.
B.

It only starts in Park and Neutral. The neutral safety switch was put on new when I put in the rebuilt transmission, the neutral safety harness to bulkhead is new. All the bulbs in the rear are new. All I did was put it in reverse and check to see if they were on. I never have a helper so it's hard to have someone look out. So I will test the connector in the trunk tonight and see what happens. As for the key in buzzer. I was confused I thought it buzzes when you just leave the key in the switch. Because relay that plugs into the fuse block says horn relay and key in buzzer and the headlights on buzzer still worked with that relay removed. Anyway the relay needs to be replaced, the contacts are burned, a wire broken, and it's missing the cover. I don't really want to pay $50 for a NOS one, but it's not available through any parts store anymore. Part # is 3579204.

I hope it's not that internal part, I just won't have reverse lights if that's the case. I'll need to check the wires in the back. I had to swap out the tail lamp assemblies and it was hard to change the sockets between the two assemblies. I need to test the body harness connector in the trunk too. Which wires do I need to jump on the bulkhead connector? Is it the brown/yellow wire?

According to the wire diagram for the 73 charger it one is black and the other is black with a tracer. meaning black wire with a white line.


It should be the only pig tail sticking out of the bulkhead, like what is in the picture. the connector has two wires going to it.

If you follow one end down, it will go down to the transmission.

Since yours is a automatic there will be one wire sticking out and going to the starter relay

Sorry I only have pictures of earlier models with manual transmission but the connector is the same and the connector you jump is the one leading to the bulkhead not the transmission side.


If you take a good quality picture of you bulkhead connector I will point it out for you.

At least I should be able to.

I'll try this weekend when I mess with it again. I've still got a front caliper leak to fix and figure why these back-up lights don't work before I pull it out of the garage again. I hope there won't be too many more major surprises when it's driven for the first time.

since 71, the NSS has its own plug arriving DIRECTLY to bulkhead conector on Bs and Es, none intermediate plug arriving to another harness like on earliers or A bodies

three wires on them ( a 4th wire directly to bulkhead plug when AC car )... two blacks to drive reverse light ( one traced ) and one brown traced yellow ( Neutral ground ). Since 72, the brown traced got a spliced signal to inside the cab to drive the seatbelts warning signal ( relay or interlock )

one of the blacks is allways powered with Key in RUN or ACC... gets the NSS and when gearing revers this closes the circuit to energize the other black wire up to rear harness.

On back of bulkhead ( inside the cab ) these wires are white and white traced, not black, but more of the same, one enregized allways with key, and the other one just when geared in R, then arriving to kick panel plug, where becomes on violet wire up to rear lights.

You can simply unplug the NSS harness from bulkhead and jump the cavities where black wires arrives, Put the key in ACC and check the reverse lights, If they turn on, problem is at harness or NSS ( or rostercomb inside the tranny as the biggest problem )

Plug it back, and now check at NSS plug underneath the car, jump both outer terminals at NSS plug... same, they must turn on reverse light. If they do, then is NSS or rostercomb.