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Unread 03-05-2011, 04:21 PM   #1
jhumphrey
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Posi Lock 4wd Light Question

So I did the posi lock swap today. It took me a little longer than I thought it would, but then again, Im not super mechanically inclined.

Anyway, I was wondering why the 4wd light stays illuminated on the dash all the time? I know its a wiring issue (of course), but I guess that I wired up the wrong wire to the light switch of the posi lock. Any suggestions?

But, it is nice to have a FUNCTIONAL 4wd system now!

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Unread 03-06-2011, 10:06 AM   #2
jhumphrey
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^^ bump
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Unread 03-06-2011, 08:24 PM   #3
timatoe
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The light is operated from vacuum. What did you do with all of those lines?
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Unread 03-06-2011, 08:29 PM   #4
linusb
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I can't tell from my phone what year Jeep you have but my light is not controlled by vacuum.

In my case, the light is controlled by a pressure switch which is activated by the shift fork shaft.

Try loosening the nut that tightens the threaded barrel into the housing. then loosen the barrel and have someone inside cab monitoring light. when light goes out, tighten the nut and test that you still get full actuation of the shift fork.
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Unread 03-06-2011, 08:31 PM   #5
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...to explain it mire simply: if the barrel us screwed too far into the shift fork housing, it will still put pressure on the switch no matter which position the cable is in.
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Unread 03-06-2011, 08:42 PM   #6
jhumphrey
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Quote:
Originally Posted by timatoe View Post
The light is operated from vacuum. What did you do with all of those lines?
The lines are still attached, but the light never worked from before. Someone had gone in and ripped out a lot of vacuum lines (the apparently swapped out the carb and nuttered), so my YJ has very few vacuum hoses. This is what led me to believe that the vacuum on the axle wasn't working right, hence the posi.

I have traced the vacuum lines up to the tcase, but wasnt sure what to do from there. The instructions state to block off the vacuum as close to the engine as possible, but those lines have already been eliminated. So what do I do with the ones that run to the tcase?

The light was on and when I ran it today, the light dimmed and went out. Keep in mind that my YJ has all kinds of electrical demons in it anyway....
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Unread 03-06-2011, 09:35 PM   #7
timatoe
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Quote:
Originally Posted by linusb View Post
I can't tell from my phone what year Jeep you have but my light is not controlled by vacuum.

In my case, the light is controlled by a pressure switch which is activated by the shift fork shaft.

Try loosening the nut that tightens the threaded barrel into the housing. then loosen the barrel and have someone inside cab monitoring light. when light goes out, tighten the nut and test that you still get full actuation of the shift fork.
In his '87 it IS controlled by vacuum, no switch at the CAD on the early ones, up to '91 I think.

OP, it is likely that either a vacuum line isn't connected properly or the vacuum switch on the firewall is bad. I don't remember right off which line I have connected to that switch, but I have solid shafts and the light works as if it were stock, I just capped off all the unused lines.
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Unread 03-06-2011, 10:00 PM   #8
jhumphrey
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Since the weekend is over, Ill have to crawl back under it next weekend to check the vacuum lines again. I found my vacuum switch, which had a couple of electrical lines coming off it it. One was black and appeared to be grounded to the body (very short wire). The second was black with a yellow tracer. Is that the 4wd light?
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Unread 02-04-2013, 10:41 AM   #9
WesYJ
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Hi All, thanks for the barrel sensor tips on the posi lok install.

I've got a very interesting report back on this. Installed my Posi Lok cable, soon as I hooked up the sensor wires, the 4wd light was on. Checked everything, as I didn't even put in 4wd yet, still on. Took advice here to loosen barrel as it may be on the sensor too tight. Well, I took the whole barrel/sensor off AND the light is STILL on?????

My vacuum system never worked from day 1 and never had any vacuum - tested with a MitiVac - so I have no idea why the light all the sudden is tripped on, even when the sensor has been removed, unless during installation I did something to trip it on that side.

ANY IDEAS......
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Unread 02-04-2013, 11:01 AM   #10
Mark05059
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what happens if you pull the cable to engage the 4x?
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Unread 02-04-2013, 02:25 PM   #11
Michaelgoesrawr
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Maybe this will help.
http://www.jeepforum.com/forum/f12/how-wire-posi-lok-kit-1434707/
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Unread 02-04-2013, 05:50 PM   #12
linusb
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Sounds like the switch is stuck in a depressed position.
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