I get a error code of 67 on my 1985 F250 302 EFI, 4 speed in the floor. The manual for my code reader says it is a neutral pressure switch error. Where in the world is this switch located??? This code comes up in KOEO condition. Any information on this problem would be helpful. I have all the service manuals but when it comes to this issue it is clear as mud to me.

 

I think this is the switch on the clutch that keeps you from starting the engine without the clutch pedal depressed, should be underneath the dash at the clutch pedal.

I am not sure of the procedures you need to use to pull codes, if the clutch pedal needs to be depressed or not.... but it looks like that's what it's complaining about.

 

It's a different switch than the one that keeps the engine from starting, but it is tied into the clutch and sometimes the tranny. It puts the computer in a different idle strategy when the truck is in neutral and/or the clutch is engaged.

 

Thanks for telling me where and what I am looking for. Also, thanks for the quick response as I will tackle this first thing in the morning.

 

I almost ran over my creeper, as this machine tried to start in gear without the clutch being pushed in! Do you suspect I am looking at two different problems?

 

I haven't worked on this exact assembly, but they may have incorporated both switches into one, or onto the same bracket, and if it's broke you may have lost both functions.

 

Thanks Dave for your valuable input. I will post my findings when I have some additional information.

 

Yes, the book says it's wired into the Air Conditioning controls, this tells me this is one input the computer uses to try and figure out if (and how much) it should raise the idle speed when the A/C is on.

 

All Manual transmission vehicles are equipped with a starter/clutch interlock system which requires the clutch pedal to be depresed all the way to the floor in order to start the engine. The system operates by means of a switch located on the brake and clutch pedal support bracket. The switch plunger is attached to the clutch pedal and extends as the clutch pedal is depressed to actuate the switch. The switch is electrically connected across the ignition switch and the starter motor relay coil to maintain an open starter circuit with the clutch engaged(pedal up)position. The switch is designed with a self-adjusting feature which provides for the switch to be set automatically with the first flooring of the clutch pedal.The self-adjusting feature consists of a two piece clip which is a snapped together over a serrated plunger (rod). When the switch plunger or rod is extended the clip bottoms out on the switch body and causes the rod to ratchet over the serrations to a position determined by the clutch pedal travel limit. The switch is now adjusted to close the starter circuit when the clutch pedal is floored. NOTE: Care must be taken to proclude maladjustment of the switch by avoiding operation or changing the "as shipped" position of the self-adjusting clip on the plunger (rod). From Ford shop manual.
CLUTCH/STARTER INTERLOCK SWITCH
1.Disconnect the connector at the switch by flexing the retaining tab on the switch housing and withdraw connector.
2.Using a test light or continuity tester check the continuity of the switch, the switch contacts should be open with the clutch pedal up(clutch engaged) and the contacts should be closed when the clutch pedal is depressed to the floor(clutch disengaged).
3.If the switch does not operate as described in step 2, check if the self-adjusting clip is out of position on the rod. If so, remove the clip and re-position the clip closer to the switch.
4.Reset the switch by depressing the clutch pedal to the floor.
5.If the switch still does not operate, replace the switch.

 

This is not true, I think it was 1984 when they started this in trucks.

My 1981 F350 with a T18 has no such switch.

 

this pertains to 1985/86 f-150 trucks, the information was printed directly from the actual ford dealership manuals. when i was in the trade back then i had seen that many times.there where numerous 4 speed trans at that time such as the ( Tod) Top mounted shifter overdrive trans, the Warner t-18 four speed trans, The Warner T-19A and T19C four speed trand as well as the new process 435 four speed trans. maybe yours is one of them. i should have specified more clearly

 

If you have the EVTM or wiring diagrams, look up this/these switches and see if there are one or two and what wire colors he should be looking at. It wouldn't surprise me if there were two switches, this was early in the computer-controlled engine game and Ford merely "added on" a lot of stuff, it wasn't until much later when functions were combined.

I don't have these diagrams from these years, all I have in this year is the Engine/Emissions Diagnosis Manual.

IOW I expect there to be a separate switch with separate wires that feed the computer, as opposed to the switch & wires that interrupt the trigger signal to the starter solenoid.

 

i have all the wiring diagrams for these ctubutis, they are in blueprint form including all makes and models/engine types, they show all connectors as well as all pigtail connections and wire color codes and code changes.they are in blueprint form. They come directly from Ford Dearborn( The Glasshouse). They are also very large i dont know how to scan them to post them because they are so big.

 

Yeah, it's a pain... I have the same for my 1981 truck as well as a few other cars I work on, they unfold and make for quite a wingspan.

If I'm using the scanner, I'll usually create I think 3 separate scans of different portions of each page, then paste them together into one using an image editing program (GIMP in my case).

But that's a lot of work, so I'll sometimes just make digital pictures (snapshots) with my camera of select portions.

The EVTMs are lots easier to work with but the way circuits are split up is sometimes annoying and makes for a lot of work, too.

Hence, if you merely mention the colors of the wires the OP should be looking for, that's enough to at least get him going. I imagine there are two switches down there - one that feeds the computer and one that doesn't - but of course that's only a guess.

My 1986 Tempo (for which I have all the Ford books) has one such switch under there that interrupts the trigger to the solenoid, and the computer doesn't seem to care if I don't have the clutch pedal depressed while pulling codes.

 

the blueprint shows the wire color to the clutch switch as(LG) light green, all the connectors to the switch are green. i can take a picture of the blueprint showing the whole thing but i don't know how to put it on here. the blueprint is dated 8/8/85