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  1. #1
    New Member
    Join Date
    Oct 2012
    Posts
    1
    Location
    parker pa.
    Tractor
    new holland tt75a

    Default neutral safety switch on new holland tt75a

    i have to jump out the neutral safety switch on my nh tt75a to get it to start. i bought a new switch and installed it still nothing. i tried innstalling it with the rearend in neutral, low, and high. nothing. reversed wire polarity, still nothing. if i bypass the switch by connecting the terminals to the switch together it starts. any ideas for me? i bought the tractor new in late 07, and it only has 51 hrs. on it.

  2. #2
    Platinum Member
    Join Date
    Jan 2012
    Posts
    589
    Location
    California
    Tractor
    Ford 7710, Ford 550, Ford 1910, Ford 4430, KD Forklift, Ford LGT17H, New Holland L255 Skidsteer

    Default Re: neutral safety switch on new holland tt75a

    Check the continuity of your switches with a tester across the posts. There should be continuity across the posts without depressing the button on the switch. Pushing in on the button should break the continuity.
    Likewise, you can hook up the switch out of the tractor to the harness. Without doing anything to the switch, turn the key to start and the engine should crank. Push the button on the switch while turning the key to start and it shouldn't crank. MAKE SURE TRANSMISSION IS IN NEUTRAL WHEN DOING THIS!
    If your switches are good, then you need to look in the bore where the switch screws in and see if there is a depression that shows up on the shift rail when the shifter is in neutral.
    It is very probable that your old switch AND the new switch are bad. Just because it is a new part does not mean it can't be faulty.

  3. #3
    Elite Member JC-jetro's Avatar
    Join Date
    Jul 2006
    Posts
    3,236
    Location
    Kansas
    Tractor
    Ford 1700, Kubota MX-4700

    Default Re: neutral safety switch on new holland tt75a

    In general clutch neutral safety is a " normally open" switch by an action of spring that keep the contacts separate. Neutral safety should not have a continuity if the switch is not pressed. Once clutch pedal is pushed by mechanical manipulation the switch should go from open to close hence completing the starter circuit and eventual crank. There might be other safeties in series that could effect starting such as PTO safety and Operator Presence control (seat switch). They all are (N.O) switches. Sitting closes seat switch and "PTO off" closes pto safety.

    JC,
    Ford 1700, 2wd.
    Kubota MX-4700DT, Gear transmission with LA 884 loader, Q/A and HD bucket.
    60" Woods Rotary Cutter, home made (3-pt boom and a Row Hipper) ,King Kutter( 5 ft Tiller,Middle Buster,Single Row Cultivator,Carry-all, 5 ft blade, 6 ft Landscaping Rake ,30" Dirt Scoop and a 4'x4' Drag Harrow)

  4. #4
    Platinum Member
    Join Date
    Jan 2012
    Posts
    589
    Location
    California
    Tractor
    Ford 7710, Ford 550, Ford 1910, Ford 4430, KD Forklift, Ford LGT17H, New Holland L255 Skidsteer

    Default Re: neutral safety switch on new holland tt75a

    In general, you are correct. A 'clutch safety switch' is "normally open (N.O.)" and your description of the clutch safety switch operation is excellently detailed.
    A 'neutral safety switch', which is usually found on the transmission shift rails, is "normally closed (N.C.). In this case, I believe that the TT75 utilizes a safety switch on the transmission, rather than on the clutch. While it is true that the PTO safety system could be a culprit, I do not believe that the 'fanny switch'/OPS/seat switch is causing the problem since bypassing the neutral safety switch eliminated the problem, temporarily, then returned when it was connected back normally.

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