Why do I still have current backfeed when the t-harness already has diodes installed??

Question

This vehicle is a 2010 Ford Fusion Hybrid I have the system installed but I'm getting current backfeed causing issues until I unplug the T-harness then it all goes back to normal?? Unwrapped t harness and found that it already has the 2 diodes as per the tech sheet!! Only wires I connected were the 2 can wires the Orange wire to ground to disarm factory security in car and the driver door pin in the sjb harness pictured on the tech sheet it actually worked to a point once but then things started going weird due to current backfeed as soon as I took the t harness out and plugged the ignition harness into it's switch and the PATS harness into its switch everything went back to normal!! So it's definitely a backfeed issue somewhere running through the EVO??? This is a hybrid not the normal fusion any and all help would be greatly appreciated!!!

Answer 1

What is the problem you are having with the car when the tharness is connected ? The diodes are in the tharness because the same output power the ignition and accessory.

Comments

it works 1 time then the locks stop working and the check engine light stays on on the dash along with the parking brake light and the airbag light If you open a door the factory alarm goes off!! Also if you try to start the car it doesn't start into hybrid almost like a circuit is dead and the PATS indicator light never comes on or does anything!! then when the t harness is taken everything goes back to how it should be!! unless I need to diode isolate my parking light relay again grabbed at the plug according also tested right with my meter!!! and was gonna grab 12 volts at the main power to the sjb not ignition!!! I'm running out of ideas I haven't tryed interrupting the ground at the headlight switch along with powering the wire at the sjb up with the relay but I don't think that would cause this problem or would it???