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pconroy328's avatar
pconroy328
Explorer
Nov 07, 2016

7 pin hitch wiring

This 2016 Greyhawk 31FK of mine seems to have a 7 pin wiring harness and a 4 pin harness below it. I haven't bought a trailer harness, but I was curious to see if I could figure out the wiring.

I was thinking of adding some back-up lights to the rear bumper and wiring them into the hitch harness.

I went out today with the voltmeter and I couldn't find 12V on any pin combination! 7 pin or the 4. I'm assuming it's wired up, but I guess Jayco could have missed it.

But should I be able to find 12V someplace on the pins? Or is there some other step I have to do to energize the harness?

I had a 7 pin diagram and put one lead on the 12V blade and the other on "ground" and nothing. Started the motorhome - still nothing. Turned on the headlights, nothing. Stepped on the breaks - nothing.

It doesn't seem to be getting any voltage at all. Am I missing a key step?

Thank you!
  • enblethen's avatar
    enblethen
    Nomad
    Nov 07, 2016
    Check the chassis owner's manual. It is likely that no fuse was put in trailer connector slot for charge line.
    It is also possible that there is no relay installed.
  • Dennis_M_M's avatar
    Dennis_M_M
    Explorer
    Nov 07, 2016
    Also make sure the ground in the connector is good. Check the pins using a known good ground.
  • Chuck_thehammer's avatar
    Chuck_thehammer
    Explorer
    Nov 07, 2016
    the charge line should be the only one that MIGHT need a fuse installed.

    all others should be ready to use...

    sounds like a bad/poor ground at your meter. or meter not set correctly.! or not working.
  • mkirsch's avatar
    mkirsch
    Nomad II
    Nov 07, 2016
    Looking at the business end of the 7-pin connector, the 12V should be at the roughly 10-11 o'clock position. Ground is roughly at the 4-5 o'clock position.

    There's nothing to figure out though, the wiring darned well better be industry-standard: https://www.etrailer.com/faq-wiring.aspx

    There is no 12V on the 4-pin connector. I am also curious why a trailer so large would even have a 4-pin connector?
  • enblethen's avatar
    enblethen
    Nomad
    Nov 07, 2016
    Many MHs come with a four pin for pulling small trailers, boats and toads.
  • petersr58's avatar
    petersr58
    Explorer
    Nov 07, 2016
    Most Ford chassis do not have the charge line wired to the seven pin connector, usually find the wire stowed about six to twelve inches from the plug (on my F53 chassis its one black and one orange wire 14 ga.). The other end is stowed near the steering column and needs to be hooked to a fuse block. Go to irv2 and search same subject line, tons of info.

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