e-drive won't work

[AlsChopShop]

the light on the dash lights up but it will not engage. i can hear hissing in the switch if i turn it real hard, but nothing when just switched over normally.

also my heater controlls (floor/defrost/vent) switch doesn't work, i think i recall mention of the two problems being vacuum related.

Al

[JeepNOFEAR]

Yup, vacuum problems. I don't know why you light comes on thou. My light doesn't come on unless it is engaged, but I have the partime kit.

[fulsizjeep]

the light on the dash lights up but it will not engage. i can hear hissing in the switch if i turn it real hard, but nothing when just switched over normally.

also my heater controlls (floor/defrost/vent) switch doesn't work, i think i recall mention of the two problems being vacuum related.

Al

The feed for this should go from the intake manifold to the vacuum ball on the firewall. then from there and vacuum line does a Y split to feed the glove box switch and the weather controls. Many times, the vacuum ball has a crack or leak in it. It is possible you have just enough vacuum that the shift rod travels far enough to trigger the light switch but not shift the tcase.

[BigRedChief]

I found out when doing the mechanical e-drive conversion that it doesn't take much movement in the t-case to make continuity in the switch for the dash light. It definitely sounds like you've got a vacuum problem somewhere.