1999 Ford F150 Pats bypass

I want to wire a Dei 555p into the vehicle in order to bypass Pats so I can run a different cluster. Since I'm not using a remote starer, I'd like to know what to use for the input or signal to the Dei module. Also if I should direct wire the input, or use a relay or whatnot. The vehicle is a 4.2l with 5 speed, if that matters. thanks

I'll take a shot at this one...

The DEI 555P usually gets a (-) signal from the Remote Starter system to know when to turn on and supply the PATS1 info to the
vehicle and allow startup. This (-) signal is applied to the 555P's Blue (-) remote start input (status) wire at Pin 3.

You could just connect this Blue wire to Chassis ground but that would mean the 555P would be on all the time. While I don't
believe that is draws much current, it might be enough to drain the battery if the truck sat idle too long ( possibly weeks ).

Another method would be to add a switch to this Blue wire. Turn it ON to start the engine and OFF when you park. While this
would not be a passive / automatic system, the bonus would be hiding the switch and providing some theft protection.

Another option would be to use the vehicles Keysense wire to turn on the 555P. This would have the 555P turn on as soon a key
was inserted into the ignition switch, preventing any unnecessary battery drain but remove the ignition immobilizer protection,
just like running the Blue wire to Chassis Ground does. Here is the trucks Keysense wire info :

Keysense      BLACK/ PINK (-)  @ STEERING COLUMN HARNESS

Use a Digital Multi Meter set to 20V DC. Connect the Red test probe to +12V constant and the Black test lead to the suspect
BLACK/ Pink wire. The DMM will go to +12V when a key is inserted into the ignition cylinder.

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Soldering is fun!