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Pin assignments for rear wiper and defroster plugs?

MikekiM

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Hoping to cannibalize one of the stocks circuits as a source of switched power for seat heaters.

I am soft top only so don’t and won’t use the rear wiper or defroster. Looks like both circuits are switched power. The defroster is timed.. is the timer incorporated in the switch or elsewhere in rig? Not sure about the viability of either circuit.

Can anyone help with details on these circuits and pin assignment?

If the defroster timer is someplace other than the switch, it could be a good source of power for the seat warmers as I don’t expect I would want them on indefinitely and a timed out power circuit could be useful.
 
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MikekiM

MikekiM

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MikekiM

MikekiM

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Can one of you electrical guru's interpret this for me please...
Screen Shot 2022-11-24 at 11.43.26.png


IMG_5171.jpeg


I want to repurpose the rear defogger circuit's switched power & ground. The connector to the switch had switch power to the blue/green tracer and I assume black is ground. Does that match the wiring schematic??

I can calculate the internal rate of return on staggered deposits to an investment account, but these wiring schematics leave me bleeding from my eyes
 
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hear

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Man, I had a series of posts where I dissected how the defogger & wiper switch worked, but I can't find them here now. This is my best recollection. The defogger is a momentary switch. When you turn the defogger on, you temporarily send ground to the instrument cluster, which tells it to turn on the timed relay. The timed relay sends power to the defogger and also the bulb in the switch. After 15(?) minutes, the relay turns off which kills power to the defogger and the bulb. I don't know for certain if it is a timed relay, or if the instrument cluster is keeping track of the time and then turns off the relay. If you press the switch again while the defogger is on (which means you re-ground the circuit), it will turn off the defogger & bulb.

On your diagram, the black is the ground wire, which is what is momentarily connected to the DB/LG wire to tell the cluster to turn it on. The power then flows to the defogger & bulb...you can see the split at C106, where BK/WT takes two routes and ultimately turns into DB/RD after C202 which powers the bulb. In short, the only switched power you have at that switch is power which is sent to the switch (on DB/RD) as a result of the switch momentarily grounding the instrument cluster (on DB/LG).

If you wanted to power heated seats off it, you'd need to probably cut the wire to the defogger somewhere after splice S320 and instead wire in your heated seats, and then also run a new ground wire (or possibly tap back into the defogger ground somewhere after splice S400). You'll want to know the current draw of the seats to make sure that 12ga is sufficient (12ga is what that circuit uses) and that your fuse is the right size.

This is the closest I can find to where I talked about it. I replaced my switch panel but wanted to retain the wiper & defogger functions.
https://wranglertjforum.com/threads/introducing-big-juicy.42177/page-6#post-1067563
 
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MikekiM

MikekiM

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Man, I had a series of posts where I dissected how the defogger & wiper switch worked, but I can't find them here now. This is my best recollection. The defogger is a momentary switch. When you turn the defogger on, you temporarily send ground to the instrument cluster, which tells it to turn on the timed relay. The timed relay sends power to the defogger and also the bulb in the switch. After 15(?) minutes, the relay turns off which kills power to the defogger and the bulb. I don't know for certain if it is a timed relay, or if the instrument cluster is keeping track of the time and then turns off the relay. If you press the switch again while the defogger is on (which means you re-ground the circuit), it will turn off the defogger & bulb.

On your diagram, the black is the ground wire, which is what is momentarily connected to the DB/LG wire to tell the cluster to turn it on. The power then flows to the defogger & bulb...you can see the split at C106, where BK/WT takes two routes and ultimately turns into DB/RD after C202 which powers the bulb. In short, the only switched power you have at that switch is power which is sent to the switch (on DB/RD) as a result of the switch momentarily grounding the instrument cluster (on DB/LG).

If you wanted to power heated seats off it, you'd need to probably cut the wire to the defogger somewhere after splice S320 and instead wire in your heated seats, and then also run a new ground wire (or possibly tap back into the defogger ground somewhere after splice S400). You'll want to know the current draw of the seats to make sure that 12ga is sufficient (12ga is what that circuit uses) and that your fuse is the right size.

This is the closest I can find to where I talked about it. I replaced my switch panel but wanted to retain the wiper & defogger functions.
https://wranglertjforum.com/threads/introducing-big-juicy.42177/page-6#post-1067563

Thanks. I ran a few tests on the rear defogger circuit and the Blue/Grn was the only line that had power, switched. And, once the ignition was on the power to Blue/Grn stayed hot.

In the end, the seat warmers I installed were crap and i got a refund, so I have a second chance to wire this and think I will put a fused distribution block behind the glove box and power from there. Haven’t gotten my head around it because, to be candid, I was pretty pissed that after the install the warmers didn’t work.
 

hear

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Thanks. I ran a few tests on the rear defogger circuit and the Blue/Grn was the only line that had power, switched. And, once the ignition was on the power to Blue/Grn stayed hot.

I don't think BG/LG should have power on it; it's an incomplete circuit except for the moment the switch is pressed, at which point DB/LG is grounded through G200. For a second you had me thinking that it had power and the switch shorted it to ground, but the diagram says it's an open circuit that closes through the momentary switch.

And as a point of order, OR will have power whenever the lights are on, and DB/RD will have power whenever the defogger is on. Both of these wires are for the lamps.

You should share which warmers you got that were crap, I know lots of us have considered this mod (powering through the defogger circuit is a novel method).
 

sab

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MikekiM:

Seat heaters are a very high-current load. There aren't many ignition + wires I would trust to run that much current through. I would recommend that you run new wires (10 gauge? - need to look at the heater draw and select appropriately) to power the heaters from the battery + (for the positive lead) and to a body ground somewhere (the ground strap on the firewall, for instance) for the negative lead. Then interrupt the positive lead with a relay suitable for the current load of the heaters. Then energize that relay with a lead connected somewhere to ignition +12V. Position your heater switch to interrupt this ignition +12V to the relay coil.

Then, when you flip the switch, the relay coil energizes, closes the contact, and the heavy-gauge 12V wire powers the heaters.
 

hear

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MikekiM:

Seat heaters are a very high-current load. There aren't many ignition + wires I would trust to run that much current through. I would recommend that you run new wires (10 gauge? - need to look at the heater draw and select appropriately) to power the heaters from the battery + (for the positive lead) and to a body ground somewhere (the ground strap on the firewall, for instance) for the negative lead. Then interrupt the positive lead with a relay suitable for the current load of the heaters. Then energize that relay with a lead connected somewhere to ignition +12V. Position your heater switch to interrupt this ignition +12V to the relay coil.

Then, when you flip the switch, the relay coil energizes, closes the contact, and the heavy-gauge 12V wire powers the heaters.

That's essentially what I told him to do, the defogger is already powered exactly as you describe, aside from you recommending 10ga vs the OEM 12ga while not knowing the power draw of the seat heaters (which I also suggested he verify). 12ga wire looks to be rated for 20A, so at 12V the seats need to be rated at less than 240W. No clue what power ranges heated seats typically operate in. But it's protected by a 10A fuse, so I guess you're going to be limited to 110W before the fuse blows. I did a bare minimum effort search, and found some heated seats that pull 45W per seat which means ~7.5A in total.

The advantage of doing it the way he's trying is that it will run for 15 min and then turn off. (I think if you turn it on a 2nd time it only runs for 10 mins, need to verify that). Whether or not running heated seats for only 15 minutes is an advantage is left as an exercise for the reader.
 
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MikekiM

MikekiM

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Thanks @sab

The kit came with relays, but no install instructions and a crazy useless inline fuse that would make you laugh. I am pulling this kit out and installing the one from Bartact. Should have bought that one when I bought the seat covers.

Going to wait to see how the Bartact kit looks before I go crazy trying to source the right power for it.
 
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