Re: F250 help? starting/relay?
i work on 89 f350's with the 7.3 quite often, i'm guessing its the same style engine as yours. sounds like the glowplug controller which is on the back of the engine, thick red wire should have constant power, smaller wire next to it power with the key on and the wavy piece of metal(glow plugs connection) should also have power then too. also check the ground which is close by. if theres no power there is most likely a problem somewhere on the passenger inner fender, thats where the main power is and the switched power which has a fusible link that can corrode or just plain burn out over time.
68 Ford Country Sedan Wagon-390 FE, C6, 9 Inch
87 Chevy Caprice Classic Wagon-307, 2004R, 10 Bolt, what can i say, i grew up with that car