89 F150. AC on Lights on. Quit running. No power even the horn. AC compressor NOT locked up. Turned light switch off. Turned AC to off. Something must have "reset?" Is there a "main" power relay?
Check the main ground from the battery to the engine block, or wherever is connects. Could be loose or corroded.
Drivability prob. as well. ck. engine light comes on at times especially when rear fuel tank is on. Now starting to occur when front tank is utilized. If you've ever switched tanks at highway speeds you know there's a "jug" before either fuel tank continues w/flow of fuel...well I'm, at times, getting that same "jug" w/o eng. light coming on w/ front tank engaged. High Pressure fuel pump located on rail, drivers side, R&R'd 9 yrs. ago. Rear internal tank fuel pump R&R'd April 2013...bad float. Lastly...knock sensor located behind intake manifold was broken when heads were replaced. I haven't been able to find new one. No one has them new for an 89 5.0 F150. So at present nothing is "listening" to the engine. I understand how knock sensors retard or advance timing. Anymore suggestions? Thanks. Les
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