Archer

Gents -

I know it's cool to have your back up lights on while driving, but having them on all the time ain't ...

Anywho, the backup lights went on last week and stay on in every gear. I've replaced the Neutral Safety Switch and no luck. Any suggestions on where to look first, besides tracing the wires and looking for shorts?

In 30+ years, this is the first time I've had to look at this.

(74 Charger, modified 727)

Thanks

Archer

sweeperking

FYI

The only thing I can tell you for sure is the back up light switch is differnt from the neutral switch. Unfortunatly I dont know what you drive so I cant help much here but for the most part there mounted on the transmission but could also be in the column.

Archer

Sweeper -

I was under the impression that the NSS controlled the backup lights. The car is a 74 Charger SE, originally a column shift, now with an after market (Hurst) shifter and reverse valve body (not the original trany). Been that way since 79 or 80, so nothing new there. Not sure about any other wires coming from the trany.

Any ideas where to look would be appreciated.

edit - this is the part I replaced, says NSS and backup ?? ??

http://www.summitracing.com/parts/SMP-NS11

Thanks,

Archer

sweeperking

Archer

Checked out your link and I guess your right I just never seen it that way, then again what I do for a living I work on a lot larger and newer vehicles. You said the lights stay on all the time, see if the car cranks in drive, if so you probably got a problem in the transmission. You could try some simple troubleshooting also. I noticed from the picture that it's a three terminal switch. Keep in mind here I dont have a schematic but it has to be a simple circuit. One of the three terminals has to have power with the ignition on. Find this with a test light and remember which one it is. The two remaining terminals, one goes to the starter and one goes to the back up lights. I personally own a power probe, very usefull tool and only costs about 30-50 bucks for a cheap one and can be used to apply (fused) power to a circuit. Any who, with the remaining two terminals, apply power to them one at a time One should crank the engine over and the other should turn on the b.u. lights. If you apply power to only one terminal and it does both functions then you have a short and need a schematic (or it would help any way)hopes some of this helps...good luck

Archer

Sweeper -

I don't think it's the switch, since replacing it didn't fix the problem and as you said, the switch is, or has to be, kinda simple in nature. The car won't start in drive or any gear other than neutral or park and the lights go on as soon as the key is turned to the "on" position, with or without the engine running. I have no idea "how" the switch works either, so that's part of my problem.

I think I'm looking at a short somewhere else, between the trany and the lights, just not sure where. Since both BU lights are on, it has to be before the wires split (I think). Any tricks for narrowing down the search?

Thanks again,

Archer

scotts74birds

Hey Archer, did you try actuating the plunger on the switch while it was OUT of the trans?

scotts74birds

Do these schematics help?
http://www.mymopar.com/downloads/197...etChargerB.JPG http://www.mymopar.com/downloads/197...etChargerA.JPG

Archer

Scott -

No, and if I'm reading you right, that makes sense! The switch and wiring may be fine (and it should be), but the thing that actuates the switch from the trany may not be! That would make sense!!!

Thanks!!! Now need to get the car back on a lift to check it out.

Guess I forgot the the NSS is, well... a switch and something has to be there to throw it

Archer

sweeperking

I guess I gave the long version but I was looking for the same result. And sometimes I automaticaly assume because the switch is new that there is nothing wrong with it. My method would have the same effect but leave the switch in the transmission and if both circuits check out then that would leave an internal transmission problem. Keep in mind that there are two seperate events happening here coming from one switch. Again, getting back to the picture of the switch from summit I see only one plunger so...that plunger has to find two seperate positions to do what it's suppose to do one for neutral start and one for b.u. If you find what position it has to be in for back up lights, well either something in the transmission may be stuck in that position or.....maybe something can be adjusted, I would look at the switch itself for maybe being adjustable.

sweeperking

Oh and Scott,

Nice schematic but my printer is busted and cant print it, too small to view on my screen

Archer

Sweeper -

I like simple

All I have to do is remove the harness from the new switch (leaving it in the trany) attach it to the old switch (which I now assume is fine), and play with the plunger to see if the I can find a position where the lights go out.

If I can, it means the throw in the trany is either stuck or slipped (and that wouldn't surprise me). That's another issue, but at least I'll have narrowed it down.

Thanks again,

BTW - try clicking on the diag, it may enlarge

Archer

sweeperking

Tried that it didnt work, just more motivation to go buy a printer. Sounds like you got a plan here...good luck