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im having trouble finding a problem with truck shutting off when headlights turned on , i replaced both battery cables and while doing so i noticed a connector not hooked to - or + i forgot to hook it back up it has 2 black wires on it and a quick disconnect .on the other side of disconnect it has a white wire connected to 3 black with green stripe the truck is '85 f150 but the engine is 80's fuel injected 5.o from mustang i did not do the engine swap and wiring is all over the place i know the black of connector would kinda indicate ground but i have a feeling it is + just from memory i dont wanna hook it up to + and have probs any ideas where to go from here i know its a stupid mistake not to do one side at a time but i just cant remember where it goes and i think it has something to do with fuel pump or injection cause i can remember the connector came undone once and truck would crank but not start until connected i know ? is kinda out there but any help would be appreciated
sounds like you might be getting juice backfed somewhere into your ignition system. throw a voltmeter on your positive side of your coil turn the headlights on and shut the key off. the second you shut your key off you should lose 13 volts at the coil. if with you headlights on you do not lose you 13 volts or it drops to like 9-11 volts then you definitly have a wire crossed somewhere.