I searched and searched, but didn't find the answer:

1993, 7.5L gas 460 cid, 5 speed manual w/ granny low 1st, 4x4, dually, standard cab & bed.

I removed the clutch interlock switch's electrical connector. I then removed both red/blue stripe wires from that conncetor, & spliced them together. I did not hook the connector back tothe interlock switch.

I did this because the truck would not start w/o violently slamming the clutch to the floorboard several times. I can't find another interlock switch, either.

With this splice, the truck starts fine everytime on the 1st try! Yea!

My question is: do I just leave the interlock connector off the interlock switch, or do I need to reconnect it? The wiring diagram I have shows 1 of the remaining wires in the connector going to the 'engine system control'.

Does anyone know anything about the interlock wiring (besides the red/blue strip wire splice)?

Please help!

 

If you have wires other than the 2 you spliced together, I'd hook it up.

 

The wiring diagram shows one of the red/blue stripe wires energized when you turn the key to crank the motor. It send power into the interlock switch which seems to have 2 relays built in.

The 1st relay sends power to the 2nd red/blue stripe wire and to the pink/yellow wire. The pink/yellow wire then send power to to the 2nd relay inside the interlock switch. This, in turn powers the grey/yellow wire, which goes to the 'engine controls system'.

The interlock connector on my truck has (in the following order): both red/blue strip wires (now removed from the connector & spliced together), and 2 solid green wires, then a purple/yellow stripe, and finally a grey/yellow stripe wire.

I am guessing the pink/yellow wire in the diagram is really the purple/yellow wire on my connector.

I do not know what the two solid green wires are for.

I feel reconnecting it is pointless, since the red/blue stripe wires no longer connect to the interlock switch.

Perhaps I should splice the grey/yellow stripe wire to the red/blue stripe wires ... to send power to the 'engine controls system' when I crank the motor over?

Anyone know what the 2 green wires are for on the interlock harness?

 

[quote=ta2rob;10775434]
I did this because the truck would not start w/o violently slamming the clutch to the floorboard several times. I can't find another interlock switch, either.

quote]

The switch is available from any Ford dealer
Part #1C3Z-11A152-AA, MSRP $85.98
Also, I'd take a close look at the linkage where the clutch pedal assembly attaches to the clutch master cylinder pushrod. The bushing there is a common wear item on these trucks & can cause just the symptom you describe.

 

"The switch is available from any Ford dealer
Part #1C3Z-11A152-AA, MSRP $85.98
Also, I'd take a close look at the linkage where the clutch pedal assembly attaches to the clutch master cylinder pushrod. The bushing there is a common wear item on these trucks & can cause just the symptom you describe.[/quote]"

OK ... there is some play in the linkage. I can see a white bushing where the linkage connects to the m/c pushrod. That's where the play is ... when I depress the pedal, it has to travel a bit before the rod starts to move.

Is this bushing considered worn out, or is there supposed to be some free play there?

Are new bushings sold separately, or do they just come with a new clutch m/c?

Anyway ... I found a new interlock switch @ Autozone for $30. They call it a 'neutral safety switch' - even though it's not an automatic.

I'll unsplice both red/blue stripe wires, reinstall them into the connector, install the new switch, & plug in the connector.

The play in the bushing has me wondering if the original switch is still good, though.

Does theis even really matter? I don't care if the kill switch has been defeated & you can start the truck in gear. I was concerned with the 2 solid green wires ... still don't know where they go. I'm also concerned that the grey/yellow strip wire (going to the 'engine control system', per the wiring diagram) is no longer hooked up.

I am fine with defeating the old interlock switch, just as long as I won't be doing any damage to the truck by having the other 4 wires on the interlock harness disconnected.

Thanks for all the help.

 

There should be no play in the bushing. It's available as a separate part from Ford, part #E69Z-7526-A MSRP $9.26.
You should replace it-if it continues to wear, you'll either break the arm on the clutch linkage or the pushrod going into the master cylinder.
I'm not aware of any issues with leaving the switch disconnected, as long as you don't start the truck in gear & run through your garage!

 

OK ... I'll see if I can get it locally @ the parts store. If not, I'll call the nearest dealer.

I'll deal with the switch after I replace the bushing.

Anything special about the bushing replacement? When I disconnect the linkage from the pushrod, am I in for any surprises, like the linkage under tension or the pushrod retracting/extending?

Thx for the part #.

 

The bushing also acts as a retainer to hold the pushrod onto the arm. It just snaps on, no spring tension or anything weird like that.

 

I got that bushing at Autozone in the HELP section. It came in a pack with several plastic bushings. I also replaced on a long time ago with a bronze door pin bushing, then slid a washer over the shaft and put a little tack weld on it. The next time mine goes I think I'll do the brass bushing or something better than stock. FestusHagen put a Heim joint on his... little overkill but its FIXED!
https://www.ford-trucks.com/forums/9...lain-evil.html
https://www.ford-trucks.com/forums/9...nsmission.html

 

That would be Dorman #14041.
You only need the four fingered clip but it's under $4 instead of $10 and you can get it almost anywhere.

 

Got it! However, much to my dismay, when I popped off the pushrod, there was little left of the original bushing.

So, little, in fact, that the linkage arm wore down considerably. Son of a ...

I replaced the bushing anyway and it still has play in the assembly ... less than before, but not much less. Doesn't change the worn linkage arm, either.

I was thinking of using a different bushing - one that will fit over the arm and into the diameter of the pushrod eye. Then use a very thin washer & snap ring (or something along those lines) to secure it to the notched area of the arm.

I also replaced the interlock switch with the Autozone $30 part. Reinstalled the 2 red/blue stripe wires back into the connector, & attached the connector to the new switch.

Vroom vroom. 1st time, every time. Nice.

Too bad about the excessive linkage arm wear. I hate previous owners who let their trucks go ...

Thanks again to everyone. I got this one fixed for less than $40 and a little of my time.

 

This is what I've done.
Purchased a oilite bronze "top hat" bushing, a couple of thick bronze washers and a pushlock style axle nut intended for a wagon or similar from the hardware store.

It took a little grinding of the nub with a Dremel tool to get it to fit over the clutch arm. (rather than making the sintered bronze busking thinner walled than it was already)
But I JB Weld'ed it in place and the next day was able to slip the pushrod, washer and pushnut on for good.

If the rain stops I'll take a pic in the daylight.