Ok, you guys might think I am insane, or genius... dunno which..
This is kind of in depth as far as electrical circuits etc. goes, so those that are more adept at wiring diagrams etc. please help out.

I looked at the wiring schematic for the IDM Relay/Security Mod (https://www.ford-trucks.com/forums/forum5/)

I wanted to modify this idea so that I didn't have to remember to click the switch "off" in order to protect the vehicle from theft. I also wanted to keep it reversible.

To do this, I wanted to use a momentary switch as opposed to a rocker or toggle switch.

The wiring diagram is about finished.
When looking at the wiring diagram, the 2 relays on the left side convert a momentary pulse of 12v+ to a constant 12v+. This will enable the IDM relay to remain on until vehicle is turned off.

The relay on the right then converts that 12v+ to a (-) output which is wired to terminal 86 on the IDM relay and activates the relay just as the original Mod did.

Here is the link for the wiring diagram (Unfinished obviously)
https://www.ford-trucks.com/forums/album.php?albumid=419&pictureid=1992

The critical bit of info I need to finish this is:
In stock form, what happens to the 30,87,87a,85 terminals on the IDM relay when the truck is turned off?
(I need to either remove the ground or 12v+ signal from the middle relay to reset the system)

Second question is: Is anyone interested in performing this Mod once it has been tested and verified to work? Or (in your opinion) am I over-engineering things?

 

Are you talking about this IDM mod by Marv?
https://www.ford-trucks.com/forums/7...nt-method.html

 

Yes he is. I linked that to him the other day when he asked about some sort of kill switch.

Skorpion007, why don't you also post this down in the 99-03 7.3 diesel section since it fits those trucks and doesn't do much for the guys here in the superduty section that have a 5.4 or a V10. The diesel section is located further down the main forum listing or here's a link to it https://www.ford-trucks.com/forums/forum31/

You'll likely get much more input on this mod from that crowd.

 

I posted in in the 7.3 section as well. Wonder if anyone finds this interesting.

 

Yes, but many of us are electronically challenged when it comes to relays, momentary switches, etc. Once you post back letting us know it works, you'll likely get more feedback and questions.

 

If you use a switched 12 volts vice a constant 12v your issue should be solved. Once you turn off vehicle 12v gone relays reset, when starting switched 12v returns but a pulse from the switch is necessary to activate the relays.

 

I am asking, not telling. If that is the case, what does that relay do? Are there any bad things that can happen if I put a kill switch circuit in using that relay?

 

You are correct the 6.0 has the Fuel Injection Control Module instead of the Injector Driver Module. The relay kill switch should work fine for your FICM too, but to be on the safe side, drop down to the 6.0 and ask them. You can link to https://www.ford-trucks.com/forums/8...th-re-mod.html
so those guys can see what we're doing and how we're doing it with the IDM. That thread contains links of other ways we've done this in the past (with pictures) so you should be able to get all the info you need.

 

Skorpion007,

Your current relay circuit will not work properly. If you want i can get into details why but to keep the thread lenght to a minimum i will try to describe the correct procedure for hook-up.
I am going to refer to your relays referenced 1st, 2nd and 3rd in your diagram as 1CR, 2CR, 3CR (CR-Control relay).

The way i have understood how you want this to work and how i have corrected it, is as follows:

when the key is in the "on" position (not start)
Push the pushbutton (1PB) (You don't have to hold it, just push once)
Then the vehicle will start when you turn the key to start.
If you turn key to off you have to repeat the procedure to start.

I am not sure what state the IDM relay needs to be in as i am not familiar with it but this circuit will be enabled at all times while the truck is on or running. This is a simple relay latching circuit.

First off this circuit can be easily done with one relay. Eliminate 2CR and 3CR.
1CR should be A DPDT relay. These can be purchased at most radioshacks. If your stuck with the Single pole relays (SPST) and insist on using them then you will need two of them 1CR and 2CR.

Below is the wiring description for the circuit. (using two (2) relays)

1) +12V (switched w/key) ties to 1CR-85, 2CR-85.
2) 1CR-86, 2CR-86, 1CR-87 tie together and run to one side of 1PB.
3) 1CR-30 ties to remainder side of 1PB and then to ground.
4) 2CR-87 ties ground and 2CR-30 connects to the IDM relay (ground break
point)

You may want to draw this out before wiring so you can understand it better.
There were a few areas of your diagram that just wouldn't or make sense.

Theory:
+12V is present once the key is switched on, applying voltage to one side of 1CR/2CR (coil). Once 1PB is pushed, 1CR/2CR will latch closing 1CR's contacts, keeping 1CR/2CR Coil enabled as long as the switched power exists.
2CR's contact opens/closes the IDM relay line to ground.

Also installing a general purpose diode 1N4004 for example across 1CR/2CR relay coil (band side, cathode of diode to +V) Can be used as a suppressor to eliminate any possible nuisance tripping.

Let me know if you have any other questions or concerns