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Fisher interfering w/ turn signals?

Discussion in 'Fisher Engineering Discussion' started by cjasonbr, Oct 9, 2008.

  1. cjasonbr

    cjasonbr Senior Member
    from Mass
    Messages: 635

    I bought my Ford truck used and it came with the plow set-up on the truck - but it didn't come with a plow. So i bought a MM2, plow only, and have been using it.

    Since last winter the turn signal relay in the dash has been intermentantly clicking. It's not the normal sound of a blinker that's two distinctly different clicks. The sound is like the first click again and again and again. Sometimes fast sometimes slow.

    I've already replaced the relay itself and the problem persisted. My next step was to replace the turn signal switch on the column. My friend was looking on all data and came across this service bulletin for me truck, that made me think:

    "09/04/06

    ADDING ADDITIONAL BULBS TO TURN INDICATOR OR HAZARD FLASHER CIRCUITS - SERVICE TIPS
    ISSUE:When adding additional bulbs to the turn signal or hazard flasher circuits, isolation relays must be used in order to prevent damage to the flasher relay module and/or the multi-function switch, and to prevent erratic operation."

    So now i'm thinking that the fisher may be interfering with the turn signal relay. The truck still makes the noise when the plow is disconnected and/or the fish-stick is turned off. Do you guys think that the Fisher may be the culprit? How can i tell if i have an isolation relay? Is there a way to go about troubleshooting this? Thanks.
     
  2. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    There's a couple likely causes of the dreaded Ford "morse code" symtom... one is the multi function switch dying. There well known for eating multi switches.

    But a just as likely a cause is corrosion in either the trailer plug socket or in the case of a Ford with either a Fisher or Western plow...corrosion inside the multi pin grill connector. This corrosion causes a back feed to the flasher relay and will make it "chatter".

    Start with disconnecting the trailer and plow plugs. The trailer wiring can be disconnected at the socket. And the plow harness should be disconnected right at the #3 and #4 ports on the Isolation module if it's a 4 port...or port #3 if it's a 3 port Iso. Try each one while listing to the relay, if it stops as soon as you disconnect one of these connectors you know where the problem is.

    If after testing/disconnecting the above plugs it still doesn't stop chattering then the likely cause is the multi function switch. A little pricey but easy to replace.
     
  3. cjasonbr

    cjasonbr Senior Member
    from Mass
    Messages: 635

    I love you B&B.

    Is the multifunction switch you're referring to the turn signal lever?
     
  4. basher

    basher PlowSite Fanatic
    from 19707
    Messages: 8,993

    :yow!::eek:
     
  5. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Correct. And they're no longer a dealer only item, they can be had in the aftermarket now. Which should give you an indication as to the demand for them.




    And double :eek:........:D :salute:
     
  6. cjasonbr

    cjasonbr Senior Member
    from Mass
    Messages: 635

    I got some q-tips and really cleaned out the plow connections. I think that may have fixed it, there looked to be a little bit of crud in the bottom. The clicking has been bothering me for the last 12 months, thanks B&B.