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F250 SD no turn signals

Discussion in 'Truck & Equipment Repair' started by Sirna, Feb 28, 2014.

  1. Sirna

    Sirna Junior Member
    Messages: 8

    So yesterday morning, one of our plow drivers came back to my shop complaining about having no hazards, no turn signals, and no brake lights.

    I replaced the aftermarket 2 wire flasher module with an OE style 5 pin flasher relay and got the hazards and brake lights to work.

    I'm getting power at the turn signal fuse.

    I replaced the multifunction switch in hopes it would fix the problem but it has not.

    Has anyone else had this problem?

    Any ideas? I'm stumped.

    The truck is a 2003 F250 SuperDuty 5.4
     
  2. Morrissey snow removal

    Morrissey snow removal PlowSite.com Addict
    Messages: 1,799

    check your grounds is there power in and out of the fuse
     
  3. Sirna

    Sirna Junior Member
    Messages: 8

    Grounds seem to be good (the ones I checked) and I'm getting power through the fuse.
     
  4. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,926

    Ck pwr in and out of the multifunction.switch for the turn signals.
     
  5. Sirna

    Sirna Junior Member
    Messages: 8

    Which terminals am I checking on the MF switch?

    I'm assuming at this point it is a wiring problem, and I'm assuming it is where the plow lights have been tied into the truck lights.
     
  6. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,926

    I don't have wiring diag with me but I can tell you tomr
     
  7. Sirna

    Sirna Junior Member
    Messages: 8

    Can you scan and upload the wiring diagram for the 03? My boss is at his wits end on this truck, as I've been toying with it for a week now and it's supposed to snow again overnight.
     
  8. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,926

    Not at home. So no book. I can take a pic and txt it to you.
     
  9. Whiffyspark

    Whiffyspark 2000 Club Member
    from SOMD
    Messages: 2,402

    Did you use a ford switch?

    It shouldn't have anything to do with the plow wiring they are just spliced in one wire each side
     
  10. Sirna

    Sirna Junior Member
    Messages: 8

    I replaced a Napa EL12 2 pole electronic flasher with an OEM Bosche 5 pin flasher relay and replaced the MF switch with an OEM new one, which I later returned.

    At first I had no brakes no hazards and no turn signals. Upon replacing the flasher with an oe relay I got hazards and brake lights back. But still no turn signals.
     
  11. Whiffyspark

    Whiffyspark 2000 Club Member
    from SOMD
    Messages: 2,402

    I'll look at schematic tomorrow but 99% sire there's is nothing between mf switch and turn signals. Use a test light and check mf out put. Do high beams wipers etc work with switch?
     
  12. Sirna

    Sirna Junior Member
    Messages: 8

    Yes. Everything on the MF switch works, with the exception of the turn signals.

    I'm thinking now it's the wiring at the relay socket.
     
  13. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,926

    Ok you have 3 fuses.
    27, 18, 34.
    Lb/pk powers the flasher also lg/rd powers the other side
    So going into multifunction switch
    Lb. And wh/rd are power coming out od the flasher and they "flash" the lights. LG is brake light power
     
  14. Sirna

    Sirna Junior Member
    Messages: 8

    I will look at it tomorrow. I actually found out my copy of alldata has the wiring diagrams.
     
  15. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,926

    Ok. Keep us updated