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4wd light issue


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Okay so I have a 1988 2.5l 4x4 (231) I just did the cluster swap and installed new senders so all gauges work. My problem is when I shift into 4wd I can hear it shift and feel it being engaged when I drive but my indicator light doesn't come on. I asked the guy who I got the cluster from if he knew wether the original vehicle had a 242 or 231 tcase he is unsure since he got it from a friend and installed it in his 2wd then he gave it to me. So any help as to why the light doesn't work.

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The lights should work regardless of which tcase it came with, the cluster and wiring are the same down to where the tcase harness plugs into the main wiring harness.

Is your CAD functional? On a CAD equipped model, the part-time light is triggered by the switch on the CAD, not by the tcase. If you locked the CAD, your light won't work.

The wires are also somewhat exposed down there, so there's a chance they got caught on something and pulled out. That happened to me a long time ago and I decided it wasn't worth fixing, but then this summer I swapped in a 242, just plugged everything in the way it was for my 231 (minus the wires and vacuum going to the CAD... I swapped in a single-piece shaft) and to my surprise the part-time light was working again. Because on a 242 it's triggered by the tcase, not the CAD.

 

But yeah, if you haven't locked your cad, check the wires running from the tcase to the front axle. Should be one orange and one black.

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They must have changed it for HO's I guess. Mine's a '91. I'll take a picture when I get home.

 

But at any rate, the bulb should have constant power to the socket, and the switch opens/closes a path to ground, wherever it is. Here's the MJ electrical troubleshooting manual for '88. Should be something useful in there I hope. I'm at work now so can't dig too far into it.

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Here's the switch I'm talking about. This is looking forwards at the back of the CAD on my '91. For reference you can see the upper control arm and mount just above it. I have no reason to believe this isn't the original axle, housing, but the truck had almost 300k miles in it by the time it got to me, so you never know.

The hex nut looking thing is the switch, the round black piece sticking out of it is where the wires would go if they hadn't been torn off long long ago.

K786fyf.jpg

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