Back up lights stay on

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Back up lights stay on

81f100custom
This is on a 81 F100 with the SROD transmission. I have checked the switch for proper operation in and out of the truck and it works as it should. When it is screwed into the plate it goes in which is indexed the lights now stay on all the time. This just started about a week or so ago. Before that they where working as they should in reverse only. I am just not sure what is going on in the part the switch screws into that is now keeping them on all the time. I have not taken this plate out yet like showing in the pic.

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Re: Back up lights stay on

Gary Lewis
Administrator
The circuit is shown on Page 46 here: Electrical/EVTM/1981 EVTM/Lights.  You pretty obviously have power to the switch on the pink/orange hash wire, but you should check.  And you apparently always have power out on the black/pink wire.

But if you go to Page 48 you'll see that it says to check the adjustment of the switch if the backup lights stay on.  
Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/soon-to-be ZF5/3.55's & EEC-V MAF/SEFI
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Re: Back up lights stay on

81f100custom
In reply to this post by 81f100custom
As far as I know there is no adjustment. If you loosen it any at all then it will not be tight and would just vibrate out. All it does is simply screw in and out. It is either tight or loose.
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Re: Back up lights stay on

1986F150Six
Could a locknut be used?
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Re: Back up lights stay on

Gary Lewis
Administrator
In reply to this post by 81f100custom
There's no lock nut on it?  Usually those have a nut on the neck that you tighten down when you get it adjusted correctly.

I'll look later today to see if I have the adjustment procedure in the shop manual.
Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/soon-to-be ZF5/3.55's & EEC-V MAF/SEFI
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Re: Back up lights stay on

81f100custom
The pic above is from the shop manual I have. I have see nothing referring to a locknut. It has worked just fine since about 1990 just the way it is. I was just thinking maybe something in the trans itself has changed or become worn maybe. The pic above looks identical to what I have plate, snap ring and switch.
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Re: Back up lights stay on

1986F150Six
Have you tried taking the switch out and connecting it to the wiring to see if the lights are on? If so, the switch is bad.
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Re: Back up lights stay on

Gary Lewis
Administrator
The 1981 shop manual says the backup light switch is not adjustable.  The catalog says that the switch is part # D8BZ 15520-A, is Motorcraft part SW-1486, and carries ID #D8BR 15520-AA on it.
Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/soon-to-be ZF5/3.55's & EEC-V MAF/SEFI