Pressure Differential Wiring
Moderator & parts slinger
Joined: Feb 2007
Posts: 50,194
Likes: 5,796
From: S/W Missouri, Polk county
Not that is is any where near the help and info from 6 by 8, but maybe some help nonetheless. I have some of the diagrams always posted here.
https://www.ford-trucks.com/forums/1...l#post14696861
https://www.ford-trucks.com/forums/1...l#post14696861
Cargo Master
Joined: Jul 2005
Posts: 2,311
Likes: 367
From: Kansas
Notice in both versions of the wiring diagrams that the pin going to the pink/white wire is grounded when the key is in the crank position...
Testing procedures for the ignition switch call for continuity between the prove-out pin and the ignition switch body.
Voltage for the warning lamp is provided ONLY from the instrument cluster.
So in order for the prove-out circuit to illuminate the bulb, it's clear that electrically both pins are the same. You can prove this by checking continuity between the two pins on the valve.
Testing procedures for the ignition switch call for continuity between the prove-out pin and the ignition switch body.
Voltage for the warning lamp is provided ONLY from the instrument cluster.
So in order for the prove-out circuit to illuminate the bulb, it's clear that electrically both pins are the same. You can prove this by checking continuity between the two pins on the valve.
Laughing Gas
Joined: Dec 2020
Posts: 869
Likes: 186
From: Near my truck
Those are great diagrams, thank you Gentlemen. 
I would never have associated ground wires with a 'live' ignition switch circuit, but it all makes sense now.
How do you upload a pdf so that it shows on the page, like yours, instead of showing as an attachment ?
I took a load of IQ Boosting tablets to work it out, but they either don't work, or I'm unfortunately immune to them.
I ran out of time in my last post, and didn't mention the tube nuts.
The M10 and M12 tube nuts in the 1995 Ranger MC require ''bubble'' flares on the lines.
The 9/16-18 and 7/16-24 tube nuts in the 2002 F150 MC require ''Double'' flares.
I bought these for my new combination valve (CV) :
https://www.summitracing.com/parts/SUM-220237
Before I threw the CV in the bin, I removed the tube nuts, and subsequently used them on my 2002 F150 MC.
The attachments show the differences between the flares, and which tube nuts are used on the CV.
I would never have associated ground wires with a 'live' ignition switch circuit, but it all makes sense now.
How do you upload a pdf so that it shows on the page, like yours, instead of showing as an attachment ?
I took a load of IQ Boosting tablets to work it out, but they either don't work, or I'm unfortunately immune to them.
I ran out of time in my last post, and didn't mention the tube nuts.
The M10 and M12 tube nuts in the 1995 Ranger MC require ''bubble'' flares on the lines.
The 9/16-18 and 7/16-24 tube nuts in the 2002 F150 MC require ''Double'' flares.
I bought these for my new combination valve (CV) :
https://www.summitracing.com/parts/SUM-220237
Before I threw the CV in the bin, I removed the tube nuts, and subsequently used them on my 2002 F150 MC.
The attachments show the differences between the flares, and which tube nuts are used on the CV.
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