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cwbymt1973 10-21-2009 05:16 PM

89 wrangler question
ok so on the firewall to the right of the battery is a mounted module i am guessing with a wire grounded to the firewall and then wires going to the main wire harness and a vaccum line comming out the bottom. where does the vaccum line go and what is this little module i cant find it in my manual.


Coyote_94YJ 10-21-2009 05:39 PM

I would need a picture of this module to make a determination but it could be either a relay or a map sensor.

The vacuum line goes to the front axle and transfer case. That little vacuum line is your only means of getting 4WD so look after it carefully or modify your front end. There are a couple ways to do that. The first is a product called Posi-Lock. It changes out the vacuum motor and lines for a cable that you pull in the cab. The second is what I did. Remove the vacuum motor off the front axle and remove the shift fork off the shaft and put a stiff spring in there to keep it engaged all the time. The 3rd option is to get a one piece axle shaft from a TJ and put it in place of your existing axle shaft.

cwbymt1973 10-21-2009 05:44 PM

i have three vaccum lines going to the front axle 2 yellow and 1 green. i am putting the pics up next

buckshot500 10-21-2009 08:20 PM

Not sure what year you have, but it sounds like this diagram may prove helpful to you.
Number one, is the big black plastic baseball under the battery. I'd bet number five is your module. Any one of the colored plastic vacuum lines can be rerouted with rubber vacuum lines from the nearest parts store.

cwbymt1973 10-21-2009 08:40 PM

that might be how its suppose to be, but not how mine is. i will have to check that tomorrow thanks alot

buckshot500 10-21-2009 08:55 PM

No problem, we prolly have even more answers to questions you haven't thought of yet!

NAVYCHIEF 10-21-2009 08:56 PM

i used the spring mod on mine and it works great.

tlrrob1000 10-21-2009 10:15 PM

Thats what the blue one is! My axle won't shift and I found the blue one with a screw capping it off. Hmmm coulsd this cause the issue? I havn't checked for a vacuum leak yet.

cwbymt1973 10-23-2009 12:32 PM

so if i was to do the stiffer spring and keep it locked all the time will this hurt the front diff as i use this as a daily driver

NAVYCHIEF 10-23-2009 12:53 PM

not really, the stuff that's there is all going around anyway. tj's have a solid front axle and they work ok. in essence all you are doing is "creating" a solid axle. it drives slightly different but not annoyingly so.

cwbymt1973 10-23-2009 01:41 PM

ok cool thanks chief, and i finally found what that switch is, its the command trac swtich vaccum operated. what kind of spring did you use on yours to make it a soild like axle


NAVYCHIEF 10-23-2009 02:15 PM

i went to ace and got one. about $1.25. just big enough to fit the shaft and about 1" long. i had to cut the one i put in till i got the correct length. they make one called a permiloc that does the same thing without and flex.i used a pretty stiff spring.

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