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Unread 10-22-2011, 06:36 PM   #1
beaver24
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89 4.2 to 4.0 swap wiring harness question

I know this has been asked a bunch of times, but I can't find anyone who fits my situation. I am swapping a 4.0 into my 89 yj. I went to a guy that parts out jeeps for an engine harness and he suggested I swap both sides of the bulkhead. He gave me everything I need from a donor YJ, but I was just wondering if that was overkill as everything I read says that wiring the engine harness is not too hard. Most people use XJ harnesses, but mine is out of a 94 YJ Should I just suck it up and do both sides or is doing just the engine harness easy enough? Can anyone help out with this?

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89 YJ 4.0 Conversion 99 XJ, 2in BDS, 1" Schackle,31 x 10.5 tires, Herc'ed
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Unread 10-22-2011, 06:53 PM   #2
94chb
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ive just finished the exact same swap. i had to use the engine harness, dash harness, and tail light/fuel pump harness. everything plugged right up. i have a thread on my swap if you wanna see pics

http://www.crossedup4x4.com/apps/for...rangler?page=2


i still gotta take and post final pics.
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Unread 10-22-2011, 07:20 PM   #3
beaver24
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How bad was the wiring swap. It just looks so overwhelming. I just figured that only 5 of them go out of the bulkhead. I guess if I'm gonna do it I should do it completly, but it looks like a real pain. Did you rebuild your 4.0? It seems like you just swapped it.
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89 YJ 4.0 Conversion 99 XJ, 2in BDS, 1" Schackle,31 x 10.5 tires, Herc'ed
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Unread 10-22-2011, 07:33 PM   #4
94chb
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its not that bad.just unplug and plug in.

i pulled everything off my 89 wrangler it was a 4.2 carb with auto trans, and i swapped in everything from a 91 wrangler 4.0 FI 5 speed.
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Unread 01-01-2012, 08:32 AM   #5
beaver24
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I finally got some time to strip this thing down and start my conversion. Engine is out 4.0 is being rebuilt. I swapped both engine and dash harnesses from a 94 Wrangler. Dash harness was a pain but it is in. The only issue I have is there are 2 connectors I cannot find a mate to. One of them is the connector that comes back through the firewall where the wires for the sensors used to come. There is a rectangle female connector say 10-12 spot that I cannot find a mate to. The other is a square blur connector with quite a few wires going to it that comes out of the harness after the Fuel Injector rail. Pics are attached. Thanks.
Chris
img_1473.jpg   img_1474.jpg  
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89 YJ 4.0 Conversion 99 XJ, 2in BDS, 1" Schackle,31 x 10.5 tires, Herc'ed
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Unread 01-01-2012, 10:03 AM   #6
jsawduste
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The grey connector is for ABS, 90% sure of it. You could trace back to the PDC relay to verify.

That black with red terminal lock goes through the firewall just above and to the right of the gas pedal..

It has the wires for all the gauges, ignition switch and a power feed. If you got a matched set of harnesses then you should see the mating end on the dash harness. It is an important connection and the Jeep will not crank without it. Nor will you have gauges.

Side note.

Wiring is not that hard if you look at it one wire at a time. A couple small tools and a wiring diagram is all you need.
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Unread 01-01-2012, 10:15 AM   #7
brentd711
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How did you connect your gauges when you did the dash harness swap? The '89 and '94 gauges are different animals.
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Unread 01-01-2012, 10:36 AM   #8
jsawduste
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Quote:
Originally Posted by brentd711 View Post
How did you connect your gauges when you did the dash harness swap? The '89 and '94 gauges are different animals.
Indeed, the speedometer is now electrically driven with a VSS signal as opposed to cable. The center information POD is different, CEL light for instance. It can be made to work but you need to understand the differences.
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Unread 01-01-2012, 11:31 AM   #9
beaver24
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He gave me the gauges with the harness so I have all that. I know its a matched set as I watched him pull the harness from the jeep. After reading your post I looked a little harder, that other connector is there so if the other one is for abs I think I'm OK on the engine harness side. Matching the wires thus far has been easy routing them under the steering wheel and taking the dash apart was the PITA. The other issue I have with this harness is that the wires from the dash to the rear brakes/fuel pump don't seem to match up. the brake lights are 3 wire on my old harness and 4 wire on the new. The other thing I'm not sure of is how the fuel pump/fuel gague connects on the new harness. The old one was in the rear brake harness, but I can't see a connector for that either.
So far the swap has been very straight forward, there are quite a few nickel and dime type pieces to get, but mostly its been OK. Having a couple of people who solely part out Jeeps in my neck of the woods helps out a lot. I haven't taken many pics, but I plan to do a writeup when it is done. Hopefully in a few weeks. I plan on having the wiring done tomorrow, then I just need to wait for the motor.
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89 YJ 4.0 Conversion 99 XJ, 2in BDS, 1" Schackle,31 x 10.5 tires, Herc'ed
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Unread 01-01-2012, 11:41 AM   #10
jsawduste
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PMing phone number
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Unread 01-01-2012, 12:05 PM   #11
94chb
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i went through all of this when i did my swap to, the tail lights isnt a big deal, the 4 wire is with a ground wire, the 3 wire doesnt, the lights ground when bolted up. the fuel pump wire is there just look
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Unread 01-01-2012, 12:14 PM   #12
beaver24
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I would assume the fuel pump/ gauge wire has a connector on it, unless they cut it accidentally? There is definitely only 2 4 pin connectors for lights on that harness. That part isn't like the front where I could overlook a connector, its pretty basic. You don't happen to have a diagram or FSM do you? Yours was a 91 so its a bit different, but maybe I can look for a specific colored wire that might be cut.
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89 YJ 4.0 Conversion 99 XJ, 2in BDS, 1" Schackle,31 x 10.5 tires, Herc'ed
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Unread 01-01-2012, 12:52 PM   #13
94chb
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i used 91 harness but i used 95 fuel pump assembly its a 3 wire plug towards driver tail light.

black yellow tracer is ground
brown is sending unit to gauge
and orange with black tracer is pump power
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Unread 01-01-2012, 06:41 PM   #14
beaver24
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Is it possible that connector comes off the engine harness rather than the body harness? There are only 6 or 7 wires coming out of the harness after the rubber boot that passes through the body. All of them go to the lights, and then there are 2 plugs black and white that come off of the passenger tail light. I see a connector on the engine harness that appears close to the correct shape and size. Does anyone know which harness the connection is on? If not I guess I'm pulling this harness out and bringing in back to the guy tomorrow.
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89 YJ 4.0 Conversion 99 XJ, 2in BDS, 1" Schackle,31 x 10.5 tires, Herc'ed
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Unread 01-01-2012, 08:13 PM   #15
brentd711
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The fuel pump/gauge wires in the '93 harness I just put in my '90 were part of the transfer case (4WD switch) & backup light bundle coming out of the PDC.
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