i have a f250 that needs to have the Nuetral Saftey Switch replaced.

it is a 1990 f250 with a 351 3 speed so im reasonable certain its a c6 trans

is it located on the shifter lever on the trans?


thanks

 

the nss on a c6 is a combination switch, nss and reverse lamps, and is on the driver side of the transmission, behind the shift lever.
it has 4 wires coming out of it.

 

its cold as hell out here in chicago and this big truck will not fit in my garage.

i have seen pics of the NSS and there are 4 wires coming out of it, i imagine 2 for reverse and 2 for the Nuetral part, is tehre 2 wires i can just jump to temperaly fix it?

 

yea, but i don't know which ones they are.

 

i got a buddy that gave me the wirring schematics.

can you help me with which wires to jump, i just cant read the colors of them to save my life. i have a c6 trans so its the one all the way on the right

thanks

 

that dont tell what is for which, just that that they are there.

 

If you're talking about jumpering the neutral safety switch, there should be a plug on the switch with the white/pink wire (ckt 33), and the red/lt blue (ckt 32). Pull that plug, and jumper it to bypass the switch. Just remember to make absolutely sure that it's in Park or Neutral before you hit that starter.

 

When you turn the ignition key to the start position 12 volts from the ignition switch goes thru the NSS (if trans is in Park or Neutral) and then to the Red/Light Blue wire at the starter relay which is mounted on the passengerside fenderwell area.

The Red/Light Blue wire is a push on connector at the relay. You may have a bad connection at that connector.

If you have a volt meter you should measure 12 volts at that wire when the ignition switch is in the start position. If you do measure 12 volts at that wire the relay should close and 12 volts from the battery goes to the starter motor.

 

well the other day it wouldnt crank at all. but when i was told to try it witht he truck in N it started, so for a couple of days i just started in N, then i had to wiggle the shifter while in N to get it to start, now it wont even crank at all. so im 99% sure its the NSS that is bad.

if i didnt live in chicago right now where its freezing outside i would just replace the NSS all together, and the truck doesnt fit in my garage so im just going to do a tempary fix until the weather gets better to fix it right

 

Well if you decide to replace the NSS here's a picture of it and the procedure to replace it.

Removal

Remove the downshift linkage rod return spring at the low-reverse servo cover.

Apply penetrating oil to the outer lever attaching nut to prevent breaking the inner lever shaft. Remove the transmission downshift outer lever attaching nut and lever.

Remove the two neutral start switch retaining bolts.

Disconnect the two multiple wire connectors.
Remove the switch from the transmission.

Installation

Install the switch on the transmission. Install the two retaining bolts.

With the transmission manual lever in neutal, check the location of the switch with the gauge pin. Install the gauge pin (No. 43 drill bit) into the three gauge pin holes.

Tighten the switch attaching bolts to (55-75 inch lbs.).
Remove the gauge pin.

Install the outer downshift lever and retaining nut and
tighten the nut.

Install the downshift linkage and rod return spring between the lever and retaining clip on the low-reverse servo cover.

Connect the wire multiple connectors. Check the operation of the switch installed. The backup lamps should operate only with the transmission selector lever in Reverse. The vehicle should start only in Park and Neutral.