My light just came on for the deterrent pin led - how to shut it off and what does it mean?

It means there's a problem with the theft deterrent system. Get the trouble codes read and then you'll have a starting point.

A link error meaning the scanner wont read or the computer wont talk to another component? Check the fuse for the ECM

It's hard to get the SECURITY light to go off when you don't know how it works ! Replacing the PCM could cause you more problems too . If a replacement PCM is being installed it must be programmed (flashed) using the latest Techline programming procedures.
Having the vehicle check for DTC ' S - diagnostic trouble codes would be the first step.
DTC P1626 Theft Deterrent Fuel Enable Signal Lost
DTC P1630 Theft Deterrent Learn Mode Active
DTC P1631 Theft Deterrent Start Enable Signal Not Correct
DTC P1632 Theft Deterrent Fuel Disable Signal Received

This anti-theft system does not use a TDM - theft deterrent module . The instrument cluster is the controlling module . Look at a wiring diagram here
http://www.bbbind.com/free_tsb.html Enter vehicle info. year , make , model engine . Then under systems click on body & accessories , then in subsystem click on security / anti-theft . Click the search button , then on the blue link .You mite be able to do a by-pass if the contacts inside the key lock cylinder is the problem . You can check it with ohm meter . The key has a resistor pellet on the side , you can check the value with ohm meter , find the two wires under the dash at the steering column . Two white wires inside a yellow or orange sheathing . There are videos on youtube !

Anti-theft system problem , possibility ! Do you have a security light blinking ? Security Indicator
The security indicator is located in the clock on the top of the instrument panel. The light emitting diode (LED) displays the immobilizer system status. The immobilizer contains the LED driver hardware for direct connection of the LED.
Vehicle Theft Deterrent (VTD) Operation
The immobilizer system design prevents vehicle theft by interrupting the engine operation. The immobilizer system prevents the vehicle from starting. The engine operating functions interrupt if the immobilizer system does not recognize the transponder identification code of the ignition key. The immobilizer system and the content theft deterrent system do not interact. The system includes the following components:
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The ignition key

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The column-mounted theft deterrent module with integrated antenna

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The transponder

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The engine control module (ECM

Is there a security light lit on the instrument cluster ? could be a anti-theft system problem ! Three electronic control modules involved in the starting circuit of this vehicle , BCM - body control module , PCM -powertrain control module , an theft deterrent module !
The immobilizer system functions are provided by the theft deterrent module (TDM) and the engine control module (ECM). When an ignition key is inserted into the ignition lock cylinder and the ignition is switched ON, the transponder embedded in the head of the key is energized by the exciter coil surrounding the ignition lock cylinder. This exciter coil is part of the TDM. The energized transponder transmits a signal that contains its unique value, which is received by the TDM. The TDM then compares this value to a value stored in memory. If the values match, the TDM will send the prerelease password via the serial data circuit to the ECM. If the transponders unique value is incorrect, the TDM will send the fuel disable password to the ECM.
When the ignition switch is placed in the Start position a discrete signal is supplied to the body control module (BCM) notifying it that the ignition is in the Start position. The BCM then sends a message to the engine control module (ECM) notifying it that CRANK has been requested. The ECM verifies that the transmission is in Park or Neutral. If it is, the ECM then supplies 12 volts to the control circuit of the starter relay. When this occurs battery positive voltage is supplied through the switch side of the starter relay to the starter solenoid.
If you knew how , in the under hood fuse / relay box is the starter relay , it has a four pin socket when relay is removed ! Two should have battery voltage , one should show ground an one is control voltage from the PCM on pin 86 , pin 85 goes to ground. Pin . Pin 87 should have battery voltage an pin 30 supply's voltage to Fuse #24 marked STRTR in the under hood fuse / relay box ! Yea , if you look on the bottom or side of the relay the pins are marked ! Check for what is missing power or control an go from there .

that's the theft deterrent system symbol Page 2-18 in your owners manual.

2004 Suburban PDF manual

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

If the chip or the "security" system for that matter is not working, you will see a light on the dash somewhere that says SECURITY. This light means that the key, ignition or TDM (theft deterrent module) is not working properly and shutting the starter off. Here is a link that explains the situation. http://vatspasslockpasskeysecurityhelp.yolasite.com/

This sounds like a starter disable feature of a car alarm. Somewhere under the dash you are going to find a box with the start wires running to it. The start wire is black with a white stripe and is thick, about a 12 gauge wire. It will come from the ignition switch and run into a relay or box. It could be installed anywhere as it is aftermarket. Once you find it, you can reconnect both ends of the starter wire and you can start it with the key. I would disconnect the power to the alarm or your lights are going to flash at random. The factory alarm (just in case it is the issue, but that isn't likely) is located behind the radio and ashtray.

This sounds like the theft deterrent feature is activated..take a look at the security light when this happens..is it flashing?? if so try a different key or you may have to replace the Ignition cylender and relearn the theft deterrent system...only done at a shop or someone that knows what their doing..

Im assuming you mean "theft". It blinks when the car is not running and is there as a theft deterrent, like a car alarms blinking LED light. Your car is equipped with Ford's PATS system, which is a fancy way of saying your keys are chipped.