Bare with me here, as I am totally talking out of my **** in regards to my idea and welcome all input.

My '91 XJ has the vacuum disconnect 4x4 Dana 30. From my observations, the t-case itself does have a vacuum switch on the rear face of the case. However, there is also a connector that research reveals is supposed to be a 4x4 indicator light switch in the axle.

My 4x4 light has failed, and it irritates me. On top of that, I believe somewhere along the lines of this bastardized vacuum setup is a leak that will make everything vacuum operated fail when the gas is pressed passed a certain point in relation to engine rpm (vacuum is lost instead of held). I plan to do the mod where the front axle is essentially permanently engaged (using the c-clip method.. I believe there is a how-to on this forum). I have attempted to unhook the little connector on the axle disco housing and bridge the plugs with a paperclip, still no light. I am at a total loss here. Which switch controls the 4x4 light? I replaced the bulb... correctly I think. All other indicator lights still work, so everything was hooked back up correctly.

If the disco housing plug is in fact the master switch, is there anyway to run those wires to where the plug is on the t-case, and remove that vacuum switch since it will no longer be needed and replace it with the simple on/off indicator switch? I just want the damn light back lol. I can snap any needed pics tomorrow.

These are the switches I am talking about (thanks google):

My disco connector (notice little connector on the left):


T-case switch I am referring to (center of t-case with 4 ports):





The vacuum switch itself, as listed by parts store:



The switch for just an electrical connection that activates the indicator light:



^^ Under the #1. Maybe I can modify one to simply make contact and transmit current or something?

Thanks for the help!


Edit: Also, anyone have a vacuum diagram for my year? I will be making a custom vacuum "ball" to replace the old one, with a better design and will simply supply vacuum to the CRUISE and the HVAC controls, which is all I can think of that will need it once the bastardized vacuum plumbing for the disco crap comes out.

 

Here's a clip lock deal (thanks to 89 Laredo) https://www.cherokeeforum.com/f51/fr...ss-91-a-38629/

Huh. Looks like the 91 does indeed have a switch and two lines. I believe the eirlier all have three lines and the switch is vac operated. I would suppose the newer type Case switch, (where there IS no disco) should turn on the light. No idea on the details there.

If I have it right there are only two lines to the vac ball. One big one to "charge" it, and a small one to the "hvac", and the cruse if you have it. Slick761 did a trick job relocating his. He has photos on his user profile.

 

I will def look into those, and many thanks!

What confuses me though is that I always figured it was one or the other in terms of switches. Why would I have both? AFAIK, everything on this XJ is stock.

Eventually I plan to get new axles for the Dana 30 with disco eliminator from Serious Offroad down the road. I don't know what to do about the t-case though. I'm OCD about little things like the indicator lights working.

 

I'm no expert. I think they only did your disco for a couple of years, might explain some of the confusion. Vac switch till 90, manual switch on the T-case when they eliminated your disco around, 92-94?....Anyway, again I'd hazard a guess that the post-Disco, manual switch on the Case is what you want. (if you lock yours)

The switch on, or activated by vacuum from the disco won't turn on the light until the fork has actually successfully moved over, verifying you are indeed engaged in 4WD.

Waz a good head scratcher when my fork broke. The base moved over, the light came on, but I remained stuck.