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While I'm here posting, I have a 99' 4x4 f 150 with no low beams. unfortunatly this started right after I reinstalled my dash (replaced my heater core). I'm guessing I pinched a wire reinstalling my dash but, someone told me it could be my turn signal / wiper tree lever. I've checked my fuses and replaced bulbs. any insight?
My truck is not equipped with day time running lights, I have fog lights but they also do not work (bulbs are good), both high and flash-to-pass work.
That points pretty strongly towards the MFS.
I'd start by getting to the connector on the MFS. You should see two RED/YELLOW wires. One should be hot anytime the headlight switch is ON (should be fine since HIGH and FTP work). The other should be hot only when the MFS is in LOW BEAM and should be off when in HIGH or FTP. If you find that the second RD/YEL wire is always dead while the first is correct, that would seal the diagnosis of the MFS.
Since you had been working on the dash, keep open the possibility that a connector might not be seated or a pin may have gotten pushed back or bent. Also, check the connectors on the I/P fuse panel, it's another possibility since the output of the MFS goes there for individual fuse protection for the fogs and left/right low-beams.
Steve
Last edited by projectSHO89; Jul 4, 2007 at 08:45 PM.