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Trailer Wiring Harness Questions


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I'm planning on creating my own harness to hook up this connector to my MJ: https://www.etrailer.com/Custom-Fit-Vehicle-Wiring/Hopkins/HM40975-11998.html

 

Because the '91-'92 taillight harness connectors are unobtainium, I decided to replace them with a 6-pin Deutsch style connector. The above connector uses 10-14ga wires for the harness, so I got the appropriate Deutsch style for those gauges: https://www.ebay.com/itm/353073619696

 

However, according to the electrical manual from an '88, it seems the wires in the taillight harness at 18ga. If I cut off the unobtainium connectors and try to splice the 10-14ga Deutsch terminals onto an 18ga wire, I'm not so sure that'll work?

 

My options seem to be:

  1. Attempt to crimp the stock 18ga wires into the 10-14ga terminals for the Deutsch style connector
  2. Use the 10-14ga Deutsch connector with a pigtail and butt connect (I have solder-seal waterproof connectors) the 10-14ga wires to the 18ga wire of the original harness
  3. Use a 18ga Deutsch connector to connect to the original MJ harness and butt connect two 18ga wires with the various 10-14ga wires from the trailer wiring harness. I purchased these style crimp connections to use, which should be able to handle the situation I'm outlining above: https://www.amazon.com/dp/B08XTV93GD?psc=1&ref=ppx_yo2ov_dt_b_product_details

    This is all assuming that the stock wires in the harness are actually 18ga, according to the electrical manual. If they're even 16ga, I think that gets me close enough to use the 10-14ga Deutsch connectors I purchased.
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Actually, I'm making this more complicated than it is. If it's truly 18ga wiring for the rear lighting circuits, it's as simple as: 

to rear ---18ga---| connector |----18ga---splice 10/12/14ga---18ga---| connector |---18ga--- to front

 

I can use my Deutsch connectors I already have, and don't have to worry about mixing and matching different terminal sizes from one side of the connector to the other. 

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Honestly, if you're going to go 7-pin, and since you're already splicing, then I would recommend at least a 7-way connector (DT 8 for example but 87-90 came with 7-way) to clean it up better and help in troubleshooting if anything ever went wrong. Plus the whole thing can easily come out if needed and you don't have to deal with cutting a thing if the trailer harness acts up.

 

image.png.b00175428cdf64d3b6871b41b2fc9fa9.png

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4 hours ago, Red Mistress said:

I have heard that ZJ uses same connectors as 91-92

Just the 1993-94 ZJs.

 

14 hours ago, acfortier said:

Because the '91-'92 taillight harness connectors are unobtainium, 

I have a few 91-92 tail light harness connectors (from early ZJs, same connector, different color wires)

MJ tail light harness connector pinout.jpeg

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8 hours ago, howeitsdone said:

Honestly, if you're going to go 7-pin, and since you're already splicing, then I would recommend at least a 7-way connector (DT 8 for example but 87-90 came with 7-way) to clean it up better and help in troubleshooting if anything ever went wrong. Plus the whole thing can easily come out if needed and you don't have to deal with cutting a thing if the trailer harness acts up.

 

image.png.b00175428cdf64d3b6871b41b2fc9fa9.png

Yeah, I’m doing a DT 6 + 2-pin weather pack for the 12V accessory and brake controller. Didn’t think it’d be necessary to add the two wires that aren’t already part of the harness into the same connection.

 

23 minutes ago, schardein said:

Just the 1993-94 ZJs.

 

I have a few 91-92 tail light harness connectors (from early ZJs, same connector, different color wires)

MJ tail light harness connector pinout.jpeg

If you’re willing to part with a set… :D

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