So I'm working through the electrical issues on my 76 w/ a C6. It has always started in any gear. I am looking at the wiring diagram and so far I am only confused.

I have two, interconnected (sorry, no pun intended), questions. I am wiring an MSD box into ignition. I have two hot wires at the Duraspark box: a green/ yellow in the 4 wire connector and a bluish wire in the 2 wire connector. I'm was trying to figure out where they originate, and that seemed to lead me to the PRNDL diagram.

And that led me, after all this time, to wonder why my truck starts in any gear.

Question 1. Any reason not to use either of the two hots that went to the Dura Spark box to power the MSD? Can I use the other for another purpose in the engine compartment ( some accessory?)

Question 2. Where is the switch that interrupts the ignition hot when the selector is in gear? Is it in the selector? Any tips on how to track down where it might have been bypassed?

I am currently in the habit of starting the truck with my foot on the brake. It's not too big of a deal yet because the truck has been too scary, for lots of reasons, for anyone else to drive. It's really starting to shape up now and it's getting to be time to fix "details" like this.

As always, thanks for all your help.

 

Can't help on the MSD wiring but the neutral start switch on the 76s is located under the dash on top of the steering column near the firewall. It sound like it has been bypassed. A previous owner probably unplugged the switch and put a jumper wire in the plug.
A common problem is the peg that activates the switch is broken or missing making it impossible to start no matter what position the shifter is in.
Just a note, the switch doesn't interupt the ignition, It interupts the start circuit so the starter doesn't turn over.

 

I'm going to go look now - it should let the truck start in both park and neutral, right?

I may have more questions after I look, it usually works out that way for me...

 

Here's what I found:
There is no switch or wiring on the steering column, but there is a rectangular hole just about where you say. If I feel inside the hole in the column, there's a round shaft and I can find a round hole drilled into that shaft - like where a pin would go.

So it looks like I'm missing the whole shooting match. Must be junkyard time.

Anyone know what years will work? Also, tips on replacing the pin that ought to be in the steering column to actuate the switch?

 

77 was the last year the nss was mounted on the steering column. 77.5-79 it was mounted in the drivers side of the transmission where the shift linkage attaches. its possible someone swapped in a newer transmission so i would check if the nss is on the transmission just o make sure.

 

There's nothing on the trans, including a back up light switch. The PO had it on a cattle ranch and probably ditched anything that wasn't absolutely necessary when it failed.

This truck has been an education. I got it for free... it was too much.

Can I adapt a trans mounted switch? It would be great to not have to try to monkey with that horribly located position on the steering column.

 

Not unless the trans. is set up for the switch. On late model C6's the switch mounts on the side of the transmission with the shift arm going through it. There are two bosses cast into the case for screws to mount the switch to. There isn't a practicle way to mount the late style switch to the early case.
Actually, replacing the switch on the coulmn isn't all that bad, the pin clips onto the shift tube and the switch is held to the column by two very short screws. This switch is also your back-up light switch.
The pin is available from Dennis Carpenter at a reasonable price and LMC (outrageous price). The switch is available from several sources all of them are around the $100.00 mark (!!).

 

i just did this on my 75 i happened to have the pin in a parts truck. but there is a thread on here where number dummy rattled off like 5 places with that pin in stock.

 

Some aftermarket shifters are available for the c6 that have neutral safety switches included in the shifter. May be more than you want to spend though. I converted mine from a stick to and automatic, and used the Lokar shifter to put the shifter on the floor.

 

For $100 you can get the GSS-2000 from Dakota Digital that gives you a Neutral Safety Switch (NSS), Back-up light circuit and circuits for gear indicator lights. http://www.dakotadigital.com/index.c...prod/prd60.htm

Or you can go with a floor mounted shifter, like the last post suggested and get a NSS and back-up light switch. I have a B&M shifter, not Lokar, but it's got the switches too.

 

or if you want to stay stock i have an extra ns/bu switch for my 75 id sell

 

C7TZ7A247A .. NSS = Neutral Safety Switch (Motorcraft SW600)

Fits ALL: 1967/77 F100/350's.

NOTE: Do not automatically assume the NSS is defective if the truck starts in gear, it could very well be something else.

1967/77 F100/350: The NSS mounts on the lower portion of the steering column above the mast jacket (steering column shroud).

The NSS operation is controlled by an inverted Y shaped pointer that fits thru a hole in the mast jacket then snaps onto the shift tube. Its pointed end fits into the NSS.

The pointer (DOTZ7B097B) is spring steel, and is notorious for snapping its pointed end off, or losing tensile strength and falling off the shift tube.

Once the pointed end snaps off, the truck will start in any gear. If the pointer is missing, the same thing occurs.

The pointer fits ALL: 1965/66 F100/250's // 1967/77 F100/350's.

Ford just obsoleted this part, but there are dozens still available at Ford Dealers, obsolete parts vendors.

Here are some sources that have DOTZ7B097B =

PARTS INTERNATIONAL in Farmers Branch TX has 18 = 888-727-0418.

GREEN SALES CO. in Cincinnati OH has 12 = 800-543-4959.

WOLFE FORD in Lidgerwood ND has 8.

ARTESIA FORD-MERCURY in Artesia NM has 5 = 505-746-3578.

JST AUTOMOTIVE in Lebanon TN has 4 = 615-443-4086.

MILLER OBSOLETE PARTS in Binghamton NY has 2 = 800-546-7278.
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btw: 1967 and later: The NSS controls the backup lights. There is no separate backup light switch with an A/T.

If the truck has a manual trans, there is a separate backup light switch.

Prior to 1967, F Series trucks were not available with backup lights.

And...according to FoMoCo, there is no such thing as a 1977.5.

This supposed cutoff date only applies to 1977 F250 4WD's (High Boys) assembled before serial number Y20,001 (midyear 1977).

 

Wow! Great information, everyone. I had no idea about the aftermarket options.

Number Dummy, I wouldn't be surprised if there's another problem. For starters, there's only a hole in the column: no pin, no switch, no wires - so, no matter what else is the problem, I have to replace it, either aftermarket or stock.

Anyone know what wires went to the switch? I am sure they have been spliced (ignition) and/or taped off (back up).

If I had the colors ID'd, I could sort through this much faster!

 

the connector for the nss is under the dash drivers side.

it looks exactly look a 4 pin flat trailer wire connector

two wires are red/blue
two wires are black/red

 

No 4 pin connector... it's been cut and spliced.

Superd02, is your extra new? Got connectors, clamps? Whatever I need, if there's nothing there?

Thanks.