How do you jump the neutral safety switch??

[mitchcj1]

Ive read up on the posts regarding no start/electrical issues and it sounds like this may be my problem. So the question is, how do you jump the neutral safety switch?? Or if possible, how do you adjust it? I have a 70 with a 351/c4. It has one plug with 4 wires. 2 red 2 black. And anyone w/ a 70 tell me which way the wires go on the solenoid posts. red w/ blue stripe on the left or right?? Ive seen both in different diagrams... Thanks

 

[Tim65GT]

I posted this in a recent post:

a '70 should be similar. The red/blue wires are the ones you are interested in. The black ones are probably for the Back-up lights.

If jumping it fixes your problem, it may just need adjusting. The switch (on a C4) allows about 1/4" of movement by loosening the two mounting screws. It's right behind the shift linkage where it goes into the transmission.

 

[mitchcj1]

So to jump, just put a wire in the plug into each of the red wire holes?? Thanks the diagram is helpful. Also, the 1/4" of movement, what am I trying to accomplish??

 

[mitchcj1]

sorry, double post

 

[jcode68]

So to jump, just put a wire in the plug into each of the red wire holes?? Thanks the diagram is helpful. Also, the 1/4" of movement, what am I trying to accomplish??

That is correct, you want to jump the red wires in the connector located at the firewall. I experienced this myself this past weekend.

 

[mitchcj1]

OK, troubleshot a little before I tried the jumper and I tried it in neutral and then held then switch to start while slowly putting it in gear. I heard a thump so let off and put in neutral and it started up!! Then I tried it in Park and it started up there too!! So do I still have a bad switch or does it need adjusting somehow. I took a closer look at it and it has two bolts but loosening them doesnt allow for any play in the switch assembly. It doesnt seem to be adjustable that way. I guess I can just crank the shifter up and down through the gears until the switch seats right?? Seems like there should be a way to get it set right. Thanks for the ideas...

 

[pabear89]

It sounds like the contacts in the switch is going bad.
Simplest way to adjust the switch(yes it is adjustable) is to put it in reverse with the key on loosen the two mounting bolts and twist slowly and have someone watch when the backup lights come on.
lock the switch down and test the start in park and netural positions.

PB

 

[mitchcj1]

Ill give that a try but I dont think my b/u lights work. So you adjust the linkage on the nut in the center. That would make sense. I thought the half moon assembly rotated... Thanks.

 

[pabear89]

If your backup lights don't work, replace the switch.
it sounds like your going to have to anyway with the internal contacts wearing away so now it won't start in park or netural.

Sometimes its best to bite the bullet and fix it.

You adjust the shift linkage on the automatic trans by loosening the center nut on the shifter, the center nut on the trans where the switch is attached controls the operating lever inside the trans.

PB

 

[Tim65GT]

So you adjust the linkage on the nut in the center. That would make sense. I thought the half moon assembly rotated... Thanks.

The half moon assembly (park/neutral/backup lamp switch) DOES rotate. If you remove one of the mounting screws, you'll see that the holes are elongated to allow for adjustment.

Like mentioned before, the switch contacts are probably worn out and it needs replacing anyway.

 

[mitchcj1]

Ok, thanks for the replies. Im sure bumping it into gear to get it to start isnt going to be good for anything. Another $100 to the spendometer.

 

[mustangdave]

Another tip for adjustment. On my 67, there is a tiny hole in the switch. You put a tiny drill bit in there for alignment (I think it was 1/64 or smaller). The bit will slip through three holes when the switch is perfectly aligned. Then tighten the two bolts down. This worked for me the first try (came from the Ford manual).

Slop in your shifter linkage doesn't help; replace bushings as needed.

 

[mitchcj1]

Just found this in one of my shop manuals. It says you can 'reset' the switch by putting it in neutral, then 1, then park, then back to neutral. Didnt work for me (think the switch is bad) but just another troubleshooting tip for everyone.