Tailgate Defrost

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Topic author
SJTD
Posts: 1924
Joined: Tue May 21, 2013 12:02 pm
Location: Lompoc, Sunland or somewhere between

Tailgate Defrost

Post by SJTD »

Can someone verify that if you push the defrost switch down it cancels the timer. In other words it shuts the defroster off.

The schematic is unclear. In fact it is in error in that it doesn't show the heater switch being SPDT center off. Doesn't show the center off position.
Sic friatur crustulum

'84 GW with Nissan SD33T, early Chev NV4500, 300, narrowed Ford reverse 44, narrowed Ford 60, SOA/reversed shackle in fornt, lowered mount/flipped shackle in rear.

sierrablue
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Location: MN/CO

Re: Tailgate Defrost

Post by sierrablue »

Same switch as the '84 I think. Pushing it down should shut it off, and the middle should be where it rests. Then up clicks it on, but it should have a timer and shut off after awhile. But it sits in the middle
'71 Wagoneer (DD)
-B350 (HEI, iron 4-barrel, Edelbrock 1406), TH400, D20
-'74 D44 front (nonpower discs)
-custom headliner
-Front shoulder belts (rears eventually)

viewtopic.php?t=23070

There are 2 major differences between new Wranglers and FSJs. FSJs are meant to be both utilitarian and capable, not just capable. FSJs are also rarely initially recognized as Jeeps by the average American.

Topic author
SJTD
Posts: 1924
Joined: Tue May 21, 2013 12:02 pm
Location: Lompoc, Sunland or somewhere between

Re: Tailgate Defrost

Post by SJTD »

Just making sure but by "should" you mean on a properly funcfuncfunctioning system, right? Pretty sure that's how mine worked before this project started.

I moved the door lock and window controls to the center of the dash from the door and it looks like I can use the no longer needed switches from from the passenger door for the tailgate.

Thanks.
Sic friatur crustulum

'84 GW with Nissan SD33T, early Chev NV4500, 300, narrowed Ford reverse 44, narrowed Ford 60, SOA/reversed shackle in fornt, lowered mount/flipped shackle in rear.

sierrablue
Posts: 1208
Joined: Wed Nov 30, 2022 8:02 pm
Location: MN/CO

Re: Tailgate Defrost

Post by sierrablue »

Right, should as in properly.

No problem!
'71 Wagoneer (DD)
-B350 (HEI, iron 4-barrel, Edelbrock 1406), TH400, D20
-'74 D44 front (nonpower discs)
-custom headliner
-Front shoulder belts (rears eventually)

viewtopic.php?t=23070

There are 2 major differences between new Wranglers and FSJs. FSJs are meant to be both utilitarian and capable, not just capable. FSJs are also rarely initially recognized as Jeeps by the average American.

runuover86gw
Posts: 208
Joined: Fri Feb 07, 2020 6:04 am
Location: Newport News, VA
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Re: Tailgate Defrost

Post by runuover86gw »

One other thing to add depending on what schematics you are looking at, if you are looking at changing out the switch. There is a diode soldered inside of the defogger switch. In the 86+, this diode was attached outside of the switch. I just solder in a 1N4004 when I am rebuilding/restoring these switches.
Josh's Classic Custom Auto Electronics LLC, Owner/Founder
https://www.facebook.com/JoshsFSJRelayKits
1986 GW 360/NP229/TF727/Dana 44's
1986 Comanche
1979 Wagoneer Limited 360/Quadra-Trac/Turbo 400/Dana 44's

candymancan
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Re: Tailgate Defrost

Post by candymancan »

Yes d9wn off. Should eveb have a light that turns off on it..at least mine does. You can even hear the relay click in the tailgate when it turns on.

Sadly my glass has multiple broken lines so it doesnt work.. even got another back glass that doesnt work because prior owners just tore the heater lines on the glass up by crap rubbing on them
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)

Topic author
SJTD
Posts: 1924
Joined: Tue May 21, 2013 12:02 pm
Location: Lompoc, Sunland or somewhere between

Re: Tailgate Defrost

Post by SJTD »

Thanks guys and thanks for that info runover. Who'd have thunk there's a diode in it from the diagram. Usually when there's electrickery in a switch they show it or show it as a blank box.

Looks like I can use the passenger window switch with the external diode.
Sic friatur crustulum

'84 GW with Nissan SD33T, early Chev NV4500, 300, narrowed Ford reverse 44, narrowed Ford 60, SOA/reversed shackle in fornt, lowered mount/flipped shackle in rear.

Topic author
SJTD
Posts: 1924
Joined: Tue May 21, 2013 12:02 pm
Location: Lompoc, Sunland or somewhere between

Re: Tailgate Defrost

Post by SJTD »

I've been trying to figger out the purpose of that diode. Maybe to "ground" the input of the defogger timer to shut it off when the key is turned off. I'm tempted to leave it out but smarter guys than me thought it was required and worth the extra money so it stays.
Sic friatur crustulum

'84 GW with Nissan SD33T, early Chev NV4500, 300, narrowed Ford reverse 44, narrowed Ford 60, SOA/reversed shackle in fornt, lowered mount/flipped shackle in rear.

runuover86gw
Posts: 208
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Re: Tailgate Defrost

Post by runuover86gw »

It is mainly used as a reverse voltage protection device. It prevents any voltage from going back to the timer and turning on the defogger unintentionally. If you look at the 90 GW rear defogger schematics, it will show you how the circuit is actually run a bit better than the older schematics. These have the diode on the outside of the switch instead of the inside, but you should be able to see how it works much better.

https://oljeep.com/gw/elec/90_numeric/9 ... age-42.jpg
Josh's Classic Custom Auto Electronics LLC, Owner/Founder
https://www.facebook.com/JoshsFSJRelayKits
1986 GW 360/NP229/TF727/Dana 44's
1986 Comanche
1979 Wagoneer Limited 360/Quadra-Trac/Turbo 400/Dana 44's

daryl2cb
Posts: 4
Joined: Mon Mar 25, 2024 10:41 am

Re: Tailgate Defrost

Post by daryl2cb »

Old thread revival,

hey runuover86GW, I just recently joined the board, tired to PM you directly but no luck. I just acquired an 83 Wagoneer and I have the same problem my switch (defrost) light is missing on the dash and rear window switch doesn't work. These appeared wired together in the diagram, not sure if that's the issue or not, but I was to gather some info from you on the steps to rebuild this switch.
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devildog80
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Location: Apache Junction AZ

Re: Tailgate Defrost

Post by devildog80 »

Check the wiring on the rear glass first, to be sure it is intact, as this might be why it does not work at the moment.
'81 CJ5 Base, 258 I6, MC2100, T176 4 spd, 300 TC, D30 Front NT, 3.31, 2-Piece AMC 20 rear NT, 3.31, 4" high arc spring lift
'84 Grand Wagoneer, 401 V8 (.030 over), MC2150 HA Comp, 727 auto, Selec-trac NP229, AMC 20 REAR - D44 FRONT - WT 3.31, 4" high arc spring lift
Rather be driving, than waiting to be modified
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