Thought I'd add two pics of the adapter harness I made for tapping ignition signal from the fuel filter heater circuit. This is a no poking wires setup and I got the idea from the BD Howler kit instructions, as that is how they get power for the circuits on the BD Howler turbo conversion. This will work on any 5.9L and avoids poking holes in wires in the harnesses to get ignition power.
i combined the wire from the fuse with the two from the ECM, using some 1/4 inch wire loom material. Ignition signal goes to the goes to the dash switch/ground to signal the ECM to operate the exhaust brake as it sees fit, and the other is a wire that makes a ground for the miniature Bosch type relay provided by Pacbrake that in turn sends power to the air solenoid. NEVER supply 12v to either of the ECM terminals, as PIN #39 is looking for a ground from the dash switch to tell the ECM to operated the exhaust brake, and PIN #42 is providing a ground to the miniature Bosch type relay coil circuit, which in turn routes power to the air solenoid thru the relay's main contact.
Pull the wheel well plastic liners and you are looking right at this stuff. Take compressed air and blow off the ECM connector blocks to remove any loose grit and dirt and use a 4mm allen wrench to remove the aft connector to push out the red plugs on holes 39 & 42. DO THIS ONLY AFTER HAVING DISCONNECTED BOTH BATTERIES. I recommend using a toothpick to push on the red pins from the pin side of the connector, You probably will not be able to grab them with tweezers or forceps from the outside of the connector as Pacbrake suggests. Push the red pins to the the outside of the connector. Push the correct wire into the correct hole and listen carefully for a click when the pin locks into place. Start the connector on squarely and gently turn the retaining screw to pull the connector into place. If any resistance is encountered, you are probably not lined up correctly.
When building up the adapter harness, you will have to figure out which end the male and female pins fit into, and use a meter to determine which wire is positive and which is negative. I seem to recall that the outboard pin is the positive, but verify it with a meter. The positive is the one you want to tap the inline fuse wire from.
My wiring diagrams show that the power leaves the fuse block as 12 gauge and at some connection prior to reaching the fuel filter, it changes to 14 gauge. The circuit is fused for 40 amps at the fuse panel. The fuel filter has a thermostat inside the black housing above the connector, it turns on the heater when the temp falls below 45°F and turns it off when it climbs above 75°F. The inline fuse is 10 amp, you are only powering the miniature relay(s) and the air solenoid, not much draw from the circuit.
I used two sections of 14 gauge stranded primary wire (like you buy in the small rolls at the auto parts stores on the boards) and 12-14 pins. I stripped the middle of the positive wire and wrapped the fuse wire end around the bare section, applied some solder and used one or two layers of heat shrink to insulate it and provide some strength, so the solder joint could not flex and break. Then I installed the pins in the connectors, and applied a short piece of wire loom material over it, but you could just as easily use some 3M 33 electrical tape and wrap the whole thing up.
Charles