brdhntr Posted March 5, 2009 Share Posted March 5, 2009 so i put the mj in 4wd the other day, now the 4wd light stays on. it sure doesn't seem to be locked in 4wd. just a light problem? easy fix? i'm just worried something could be froze up or binding. :dunno: Link to comment Share on other sites More sharing options...
Darren Posted March 5, 2009 Share Posted March 5, 2009 put a black piece of electrical tape over it, and call it a day. ok try shifting in and out of 4wd and or "wiggling" the shifer. Link to comment Share on other sites More sharing options...
jtdesigns Posted March 5, 2009 Share Posted March 5, 2009 Isnt there something about the CAD and vac lines that causes that? Link to comment Share on other sites More sharing options...
Wildman Posted March 5, 2009 Share Posted March 5, 2009 There is a switch on the right fender, under the pressure bottle, behind the heater blower that has a vacuum line to it from the transfer case switch (to the CAD) this switch "sticks" and has a wire that feeds the 4wd lite in the dash, my one was alway on, and I disconnected the wire so the light don't light at all any more........do I know the truck is in 4wd......yea, I can feel it. The replacement switch is like $40+ if you want to go that route. Link to comment Share on other sites More sharing options...
maddzz1 Posted March 5, 2009 Share Posted March 5, 2009 There is a switch on the right fender, under the pressure bottle, behind the heater blower that has a vacuum line to it from the transfer case switch (to the CAD) this switch "sticks" and has a wire that feeds the 4wd lite in the dash, my one was alway on, and I disconnected the wire so the light don't light at all any more........do I know the truck is in 4wd......yea, I can feel it. The replacement switch is like $40+ if you want to go that route. Could this also prevent the light from coming on? Got a pic of it? if not, ill follow the line up from the cad. Link to comment Share on other sites More sharing options...
BLHTAZ Posted March 5, 2009 Share Posted March 5, 2009 The vacuum switch on the t-case has been known to stick enough to cause the light to come on, but not enough to engage the CAD. I had that problem when I first got the MJ and it happened on my YJ too. Link to comment Share on other sites More sharing options...
Pete M Posted March 5, 2009 Share Posted March 5, 2009 My suggestion to every MJ guy/gal out there; remove all the vacuum actuated crap in the 4wd system, shim the CAD to be engaged all the time, and then rely solely on the huge shifter handle next to you to tell if you're in 4wd or not. :D Been working great for me in my ex-2wd 88. Link to comment Share on other sites More sharing options...
jaekl Posted March 5, 2009 Share Posted March 5, 2009 The vacuum switch on the t-case has been known to stick enough to cause the light to come on, but not enough to engage the CAD. I had that problem when I first got the MJ and it happened on my YJ too. Looking at the schematic the vacuum routing to the switch is not complete until the CAD is fully actuated. Basically, it's vacuum to the transfer case where you select vacuum to connect the right axle shaft of disconnect it. That's the three tubes to the selector. Then the two output tubes (on or off) go down to the axle to move the dog clutch where you want it (on or off). The third tube from the axle goes up to the light switch. At the right fender well is the switch and a couple of check valves and a vent. If you want to keep it, ensure you have vacuum to the selector, make sure you have vacuum for on and off to the axle and make sure the CAD actuates with vacuum. If all of that works, then all of the problems are at the right fender well and need to be fixed or patched. Once you start looking at it and thinking about it, it becomes obvious how it works and what needs to be fixed. Link to comment Share on other sites More sharing options...
BLHTAZ Posted March 6, 2009 Share Posted March 6, 2009 Not worth the effort. Do as Pete suggested and forget about all of that useless crap ;) . The light is not needed as stated above...you should know if you are in 4WD or not without a light to tell you :thumbsup: Link to comment Share on other sites More sharing options...
brdhntr Posted March 8, 2009 Author Share Posted March 8, 2009 yes, i can tell when i'm in 4wd. i was more concerned withe something being frozen that is keeping the line open. we've been having some nice temps that get the moisture in the air and then below zero that freezes everything solid. when this happens, it's not uncommon for lines to freeze, even air and vacuum lines. things warmed up the other day and the light went off. 4wd works fine and the light works without a problem now. :clapping: Link to comment Share on other sites More sharing options...
mvusse Posted March 8, 2009 Share Posted March 8, 2009 There are exceptional cases where you don't want it to always be engaged. I have a front locker and because of that want the axle disengaged when winter comes back while in 4wd. I could just unplug the lines, but I think I'm going to run the while CAD deal through a home made posi-lock, and see if I can run the axle engage vacuum line on the transfer case straight to the light switch. Then again, my light quit working at some point this winter, and I'm thinking burnt out bulb. Link to comment Share on other sites More sharing options...
Wildman Posted March 8, 2009 Share Posted March 8, 2009 yes, i can tell when i'm in 4wd. i was more concerned withe something being frozen that is keeping the line open. we've been having some nice temps that get the moisture in the air and then below zero that freezes everything solid. when this happens, it's not uncommon for lines to freeze, even air and vacuum lines. things warmed up the other day and the light went off. 4wd works fine and the light works without a problem now. :clapping: Your just going to have to move to a warmer climate........then you never have this problem again :D :teehee: Link to comment Share on other sites More sharing options...
brdhntr Posted March 9, 2009 Author Share Posted March 9, 2009 yes, i can tell when i'm in 4wd. i was more concerned withe something being frozen that is keeping the line open. we've been having some nice temps that get the moisture in the air and then below zero that freezes everything solid. when this happens, it's not uncommon for lines to freeze, even air and vacuum lines. things warmed up the other day and the light went off. 4wd works fine and the light works without a problem now. :clapping: Your just going to have to move to a warmer climate........then you never have this problem again :D :teehee: i heard that!!!!!!! :rotfl2: :rotfl2: :rotfl2: :rotfl2: Link to comment Share on other sites More sharing options...
Geonovast Posted March 9, 2009 Share Posted March 9, 2009 Pop the gauge cluster out and pull the light bulb for it. I've done that with every cluster I've had to get rid of that shift up light. :fs1: Link to comment Share on other sites More sharing options...
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