Having a prob with a fault in the starter lock-out that's activated/deactivated by the brake pedal on a 94 F250.

Previously, it worked as expected - no foot on the pedal = no start. Lately it's been starting (kinda) without having the pedal depressed. The sound now when starting with foot on or off the pedal is a little different than a normal clean start - almost like there's some sort of mechanical interference (which I'd be surprized if there were, but that's what it sounds like).

It's been getting worse over the past few weeks, and now to the point that it won't start until I mess around with it some.

I think the switch at the pedal is OK since there still is some effect if I hit the brake when starting - seems to turn over better.

I'm guessing that there's some sort of relay in that circuit that controls the lock-out, but I have no idea where to look or
exactly how that circuit works. Any pointers?

 

Is this an automatic? I fso i just changed mine and can give you the entire procedure for changing the MLPS and how to do the plug conversion..

 

Yes. Auto. Any help would be greatly appreciated.

 

OK, I'm confused. I didn't think the neutral safety switch had anything to do with the brake pedal. I thought you just had to have the tranny in Park or Neutral. I know I don't have to touch the brake pedal on my '95 F150 for it to start.

 

Don't know if I'm using the right terminology or not for the control, but in my 94 F250 it definately requires a foot on the brake to start even in park. Or it did anyway... it's kinda put itself into auto-bypass mode now.

 

I recomend going to napa and getting it from there. $35, Ford $90.
Dissasembly: You need a 12mm for the nut on the arm. And i think 10mm for the hold down bolts. Being yours is a 94 it will ahve the old style plug which will need changed. The reto parts will be in the box with the new switch. While your underneith the truck the easyest way to convert the plug is to pull the compleat harnes over the tranny. You will need to remove the heat shield covering the plug on the pass side, unplug the o2 and the tranfercase indicator. it is attached to the top of the tranny with some tape on a strip of metal. Pull it off themetal. you should have enough harnes down to let the plug hit the ground. I recomend soaking the blots on the switch for a few days with penetrating oil. Remove the big nut that goes through the switch. As you put force on it the lever will click theough the gears till it stops. Don't worry, let it hit the stop and then you can put some force on it. After the nut comes off remove the hold down bolts. Spray the cable end with lub and pry it off the shift arm (two flat screwdrivers worked for me). Remove arm, Pry the old swith off.

Reasembly: Put the arm that you took of back on the and get the tranny back into N. You will notice a N location on the new switch. Make sure the lines on the switch line up with each other and it should slide right on the stud index mark perfect. bolt it back up.

Harness: Your factory harnes is rectangular and the new one is oval. The directions with the switch are very good at describing this process. You will have to pop out each wire and insert it through the new cap, rubber gromet and into the plug body. Rerun the harnes and plug everything back in.

Rememberif you wired it wrong it will not start so you might want to write down all the wire colors in there locations.

If you need any other info let me know.

 

So if I read youur directions right, I need to replace/convert the MLPS to a new type and that's located on the trans housing? If I look at the shift control arm on the trans I should see the MLPS and it should sit around the arm?

My problem seems restricted to the brake activation/deactivation versus the position of the shifter - that still works as expected. Would this still apply?

 

Previously, it worked as expected - no foot on the pedal = no start.

If you have to step on the brake to start your truck then someone has rewired it.

 

I've never seen any vehicle that needed the brake pedal depressed to start the engine. This doesn't seem to be standard. The MLPS sensor keeps the engine from starting when not in neutral or park. It's not connected to the brake pedal.