Manual trans Clutch Lockout Switch

In this thread, I suggested to Iowa Tom to verify that the manual transmission is not engaged while doing some starter tests, to ensure that the truck won't jump ahead.

My friend Jim answered me that this should not happen, since there is a security switch on the clutch that cuts the ignition circuit if pedal isn't depressed.

So this topic is specifically about this famous clutch switch.  I never saw it in Big Bro...

Jim - The problem with the diagrams reading is that they do not clearly indicate where the connectors/switches are located, neither how they look.

If I had a better idea of what I should be looking for...  But really, I didn't see any free connectors or switch around the clutch pedal.
And while rebuilding Big Bro, I had a good view of the wiring.



Any picture or description of this famous clutch switch?
Maybe not under the dash, but somewhere else on the truck?

Here's a photo showing where it mounts. I'm pretty sure cruise control (or some other accessory) uses the same switch, hence why there's two connector spaces on the switch. Trucks without cruise control seem to have an empty connector in the cruise control spot. (Cruise control uses two switches if I remember correctly)

Even with a clutch switch, it's always a good practice to chock the wheels and keep the transmission in neutral. I'd rather trust the shift lever's mechanical connection over an electrical one.

I tried to get pics of the switch and plug C190 up behind the fuse panel.
You see some of circuit 32 comes out of the main harness, giving enough of a whip or pigtail to reach the switch.

So the harness side of C190 plugs into the left side of the switch itself, that Shaun shows.
('Speed Control' also has an input from the brake lights to disengage)

Thanks Shaun and Jim!


With your help, I now have a nice story to tell:

«Once upon a time, in a far far away country, over the North Winter Wall, there was a big Bullnose named Big Brother, that was equipped with a nice Clutch Switch.  But it happened that a mysterious mechanic has stolen it.»

Shaun I reproduce your pict with numbers on it, followed by two picts I took this morning in Big bro.
The brackets #1 and #2 are still there , but no sign of any connector:




Since I had couple of manual cars (Beetle, Renault 5, VW Jetta) that were not equipped with such security ignition switch, I never realized that Big Bro should.

BigBrother-84 wrote

Jim - The problem with the diagrams reading is that they do not clearly indicate where the connectors/switches are located, neither how they look.

If I had a better idea of what I should be looking for...  But really, I didn't see any free connectors or switch around the clutch pedal.
Any picture or description of this famous clutch switch?

Jeff, you have to go to the last pages of the chapter to get to the illustrations (it's not that they aren't there!)

I don't often post them because I'm working from a phone and most questions are directed at the circuit, not the component

Jeff. You're an architect right?

If you had a plan view marked Sec A>--            --<A.  (Sorry this is my lame attempt at making a graphic)  <smiley image="smiley_teeth.gif"/>
You'd "get it" that that section was represented after the 'plan' and perhaps elevations for "forth floor" or whatever, and likely already have a picture in your head after seeing the plan and elevation views, right?

It's not dissimilar here. These books were written for the dealership mechanics who if they hadn't seen the specific model, issue or component were likely familiar with it from other vehicles of the same brand.
When they see a coloured triangle with a letter and "see page 91" they probably already know what they'll find on pg 91.

It was much the same when there were paper catalogues behind the parts counter.
You didn't flip through 1500 pages, you cracked the book open to within a couple of pages of what you needed even if there weren't tabbed sections.

An EVTM hard copy is an excellent tool if you're familiar with it.  

Hey BigBrother,

Do you need a clutch switch? I happen to have a brand new one, still in the Ford box;).

I can send it to you if you want it. Free to a good home as it were;)

Hi Cory,

That could be a nice project for next summer!


Although I'll have to dig and find where in the harness are hidden the good wires...  And also find a connector (my local salvage yard?).

I'll send you an email, to see how to conclude it.  If you don't receive it, Gary could send you my personnal email.

Can't send the email...  Locked in the "robot verification".

Thanks Jim.  Don't know why, but I find not easy to search for what I'm looking for in the EVTM.  I have the PDF indexed file, but searching by word (clutch switch, for example) doesn't always give a good result.

As for the diagrams...  they are made by engineers, for engineers.


As architect, I can read at them, but I largely prefer a 3D view.

First I did not check the link BB posted so .....

A lot depends on the year of the truck as they all dont have a clutch lock out so the starter will not crank till the clutch is pressed in.

I say this because my late 80 (its a 81) and my early 81 F100's both manual transmissions, dont have the switch or the harness to hook the switch to.
Heck I dont even know if you could mount the switch to the pedal bracket and then make your own harness? Well I guess you could be why?

I was told from day 1 always always push the clutch in before touching the key to start a manual transmission car or truck.
Dave ----

Yep
That's why I said hydraulic clutch ('83 for 460 & IDI, '84 for Windsors and the 300/4.9)

You were given sage advice.  

BigBrother-84 wrote

Can't send the email...  Locked in the "robot verification".

The email came through...8 times...lol. I will reply to your email also.

May need to confirm exactly what this switch is, but I think that it is a factory clutch switch. I bought it years ago for my 1984 Bullnose when I was going to install an aftermarket cruise control. My memory is getting kinda fuzzy on the topic...this thing has been on my shelf for quite a while.

Sorry guys...it is not the clutch switch, it is a cruise control interrupt switch...my bad...

https://forum.garysgaragemahal.com/Cruise-Control-Interrupt-Switches-No-Longer-Available-as-of-7-29-19-tp29006.html

https://forum.garysgaragemahal.com/Cruise-control-clutch-switch-E3TZ-9F645-B-tp15141.html

I was wondering what happened to the cruise control switches that were on my pedal assembly. Now I remember. lol.

salans7 wrote

I was wondering what happened to the cruise control switches that were on my pedal assembly. Now I remember. lol.

 Haha

Interesting thread.  That picture of the inside of the cab with the dash removed and all the wires exposed gives me a little bit of anxiety.  I loathe removing dashes.  

My '86 has a clutch lockout switch, and one of the first things I did when I got the truck was unplug it or put a jumper wire in it, whichever was the case to bypass it.  

You can easily bypass them by inserting a spare fuse in the harness plug.
It only has to pass enough current to trigger the relay.

Be careful.  Big Blue's PMGR starter was able to start that 460 while hooked onto a loaded trailer.  The truck was going somewhere.

Now that you say that, this is exactly what I did, probably after reading that it would work on this site a couple of years ago.  Which also explains when I was looking under the dash recently and I wondered what in the heck that random plug that had a fuse could possibly be doing.  I'll forget all of this when I'm under the dash in the future I'm sure, and I'll wonder what's going on again.