[CLIMEY]

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Hello, just bought a 91 wrangler and the 4wd light does not come on neither does 4wd work period high or low he vaccum lines and the 4wd motor or whatever engages it all seem to be in tact what should a young boy like me do if the 4wd is shot would posi lock be a better easier option to put on

Also my temp guage dosent what, what is going on help would be much much appreciated

[mtn_wrangler]

Originally Posted by CLIMEY

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Hello, just bought a 91 wrangler and the 4wd light does not come on neither does 4wd work period high or low he vaccum lines and the 4wd motor or whatever engages it all seem to be in tact what should a young boy like me do if the 4wd is shot would posi lock be a better easier option to put on

Also my temp guage dosent what, what is going on help would be much much appreciated

for the 4wd did you try engaging it by putting vacuum straight to the line to engage the 4wd?

[CLIMEY]

no and i have not a clue how to do that is it difficult

[mtn_wrangler]

Originally Posted by CLIMEY

no and i have not a clue how to do that is it difficult

nope just take a vacuum line that is constant vacuum and with the engine running hook it into the line that is closest to the passenger side on the axle i believe and if that turns on the 4x4 light then you should also have the 4x4 working

[geusey]

Im gonna go posi-lock one of these days. There are too many vac lines on my jeep anyway and its 16 years old, so they're going to fail eventually. Just waiting paitiently.

[CLIMEY]

i popped off the lines that suck air in theres two hoses or lines i guess and the left one sucked in when put into 4wd and the right one sucked in when taken out of 4wd would the accuator be bad thats the thing i pulled the wires out of it kind of looks like a saucer or disk thanks for the help gentelman

[RCHavok797]

Sounds like the vacuum motor is bad. I had to replace mine in the winter after checking all the vacuum lines to make sure they were not the problem. The saucer shaped thing is called the vacuum motor.

[CLIMEY]

the peice i pulled off the vaccum motor(the disk or saucer) had two lines and the one on the left was sucking when my old lady put it in 4wd and the when she put it out of 4wd the one on the right was sucking in also so both of the were sucking right which means theres no cracks in the vaccum lines at all right?
So what i need to do to make the 4wd work is replace the vaccum motor (the disk or saucer thing) and it will be working properly again?

[geusey]

Originally Posted by CLIMEY

the peice i pulled off the vaccum motor(the disk or saucer) had two lines and the one on the left was sucking when my old lady put it in 4wd and the when she put it out of 4wd the one on the right was sucking in also so both of the were sucking right which means theres no cracks in the vaccum lines at all right?
So what i need to do to make the 4wd work is replace the vaccum motor (the disk or saucer thing) and it will be working properly again?

Sounds about right. All signs seem to point to the vac motor. Good luck and happy wheelin

[JeeperDon]

Another test: Jack up the right front tire. Start the engine, neutral, parking-brake on. Put the t-case in 4wd and try to turn the right front tire by hand (it should not turn (maybe a partial turn, then not). Put the t-case in 2wd and try the tire again, which should turn. If that all works, the 2wd/4wd is fine, and you have an electrical problem. Did you check the bulb?

[stu1021]

My Chilton's has almost a page on diagnosing the "command trac" system. I could scan it with the diagrams and send it to you if it would help. Like JeeperDon said, start with the "jack up the front right tire" test. If it doesn't pass this test, and you have a vacuum issue (lines or vac motor) then you might try borrowing or buying a small vacuum pump (you squeeze it to generate vacuum and it has a gauge on it). You could also use manifold vacuum from the engine with a length of tubing - your call. You have three ports on the vac motor (saucer/disk thing on the axle). Apply vacuum to the port on the face of the disk, wait 15-30 seconds and try to rotate the front wheel - axle shafts should be disengaged and the wheel should turn freely. Now, apply vacuum to the port that is on the edge of the big disk. At this point, you should get vacuum at the third port (the one on the skinny shaft that mounts the unit to the axle). The third port is one that connects to the switch for the indicator lamp. Wait again and try to rotate the tire. The shafts should engage and the tire will not rotate freely. If any of these things do not occur the vac motor or possibly the engagement fork under the cover are bad. If you have to replace one part, it is probably a good idea to replace both at the same time. You will want to lift the right wheel as high as possible when removing these so that axle lube doesn't run out.

[RCHavok797]

The vacuum motor engages the front axle and trips the switch for the 4wd light. Everything you described and your troubleshooting point to the vacuum motor being bad.

[RCHavok797]

http://www.quadratec.com/products/52432_01.htm. That is the one I bought.

[CLIMEY]

tried the jacking of the axle and turned the tire in 4wd and 2wd it turned in both 4wd and 2wd i am going to try the things that stu1021 told me i also ordered the vaccum motor from quadratec hopefully it is just the vaccum motor and it just needs tobe replaced thanks for the help i hope it works

[JeeperDon]

Originally Posted by CLIMEY

i also ordered the vaccum motor from quadratec hopefully it is just the vaccum motor and it just needs tobe replaced thanks for the help i hope it works

So you decided not to pull the present motor to see if it can be easily fixed first? Just went out and bought parts? Can I have a grant?