TL/DR version: is there an armature or such inside the upper t-case which engages the switches?

Longer version:

I hate to hijack/bump, but can't post a new topic at this time.

Not a 4R owner, but work on many. This forum has been a great resource, thanks to all for your contribution in providing it, and thanks to OP for pointing toward the right part #s.

I'm currently working on a 2000 SR5 (J shift, auto) and having a somewhat similar problem.

The transfer case does shift to all positions fine, and is engaging the forward driveshaft, but no dash light and front diff doesn't seem locked when driving.

Checking the 3 switches (4HI, 4LO, N) shows no continuity on any in any shifter position. I assume the switches are bad, but do feel it's odd that all 3 are out.. (Just to note it, jumping the 4HI switch plug activates the 4wd. Rest of system working.)

My question is: is there an armature or such inside the upper t-case which engages the switches? A different way: is it possible that something is missing/bent/broken and causing the switches not to get pushed?

If anyone has an answer, great, would save some time/$. Thanks for your time, in any case.

Here is a good thread. might help.
4WD won't disengage on 99 4Runner LTD - YotaTech Forums

Spartacus,

Thanks for the reply, and definitely good info in that thread. Useful diagrams as well.

The j shift type is much simpler than what most of the posters there seem to be dealing with. From what I understand (for 2000), it's just mechanical shift on the t-case, which then activates one of 3 (t-case) switches to tell ecm/tcm to go to 4wd, and those switches tell ecm/tcm to activate VSV, which then sends vacuum to the front diff actuator, and, when actuator actuates, front diff switch sends confirmation and lights the dash light.

Since I can jump the t-case switch and lock it in, I assume ecm/tcm, vsv, f diff actuator and switch are all fine.

The boggle is just what internal to the t-case pushes the switches in. Since they're about 3 inches rear of the shift lever, I assume there is a slide or armature that gets pushed by the shift lever to switch the switches.

No diagrams show such, but that definitely doesn't mean that it isn't there.. More likely, just not what they intended to show on the diagram.

Damned if you do, damned if you don't.. If I go pull a switch to feel if there is a slide there, probably $80 charge to go and check. If I order the switches beforehand, can swap at about same price labor-wise, but there's a possibility I'm left with $220 worth of switches the customer doesn't need..

If it was mine, I'd probably throw a 15$ pushbutton toggle in there and be done with it.. 2wd low would probably be a fun option for lugging up hills..

I would recommend removing the switches and bench testing for continuity. I had to clean all my switches with contact cleaner to get good and consistent continuity. If the switches test good for continuity when compressed and the system still doesn't function correctly after reinstalling the switches then that would confirm an internal problem with the transfer case.

I just changed my transfer case switches on 96 limited from above, it was tight, but got it done. Be careful not to lose the clip underneath that connects the shifter linkage. It was certainly easier than fighting rusty cross member bolts for me. If you have big hands it might be tougher. I did get underneath to start the new ones in. But tightened them up with 27MM wrench from above. I used 3 of the masterpro (Taiwan) 2-8950 backup light switches from Oreilly'$27.99 ea. I tested them before putting them in, the resistance varied among them. They were exactly the same as the Dorman 600-554 at $47 ea. Took it for a test drive and still having some intermittent shifts. But got rid of the vibration that I had. I thought I was looking at major repair to the front dif. I'll have to do some more checking tomorrow. Still comes out of 4WD rather hard.

My first post here, thanks to all of you who have posted on this topic, it made my repairs so much easier.

It appears that my transfer case top right switch is failed open. A jumper in the harness connection restores the VSV toggle from restraint to engage for the front actuator and lights up the dash symbol for four wheel drive. I may install a toggle switch manually operated from inside the cabin as a work around to the near hidden T case switch requiring me to butcher the tunnel or contort like Houdini from below....

My question is what functions do the two switches on the left side of the T case perform? Input to the ECU and transmission for shift points control?

One is the 4LO switch, used for transmission shifting (goes only to the ECU). One is for transfer case neutral - turns on the "AT/P" light on the dash if the transmission is in park and the transfer case is in Neutral (warns you that the parking pawl won't hold the vehicle).

-Charlie

If you unbolt the transmission crossmember you can lower the transmission enough to get to that transfer case switch FYI

Thanks Charlie for that information on the other two switches and Bad Luck for your input. If the cross member is out of the way how low can you get the T case before something is binding or interfering at the fan end of the engine? I have just finished with the flex plate removal and replace, vacuum actuator remove, rebuild and install. It is a lot of ground time under the truck so I am really tempted to go through the tunnel wall with a cut off wheel. Or just go substitute manual with a toggle switch in the cabin. You guys probably hate that idea though........

Toggle switch will work as long as you know what the switch you are controlling is telling the vehicle to do and don’t forget to turn it on/off as necessary. I had mine sagged quite a bit. I think the limiting factor was the rack/crossmember by the rack coming in contact with the engine/transmission bell housing. I had to use an open end wrench and a few curse words to remove the switches when I was cleaning them for a 4wd issue. I supported the transfer case with a jack and removed the whole transmission crossmember, but I think just removing the transmission crossmember to frame bolts would be sufficient.

So on a 99 4Rnr, MT, V6 SR5, *should* there be a low-range indicator light? 4X4 works, and there is a green indicator light when it goes into 4X4, but no indicator when it goes into 4L. I have confirmed my 2 (two!) transfer indicator switches are working correctly.

??

No Low Range switch on the MT - that is only used for the ECU to control shift points on the J-shift case.

-Charlie

The ECU has no control of shift points on MT.....right? I confirmed that the drivers side normally open switch does indeed close on placing the xfer case in low range. The very hard to reach switch on the passenger side detects shift into 4X4. So yes, this is a low range switch on MT.

I rarely drive this truck, but wife was insisting there was a low range indicating light that's not working.

About four years ago I installed a manual toggle switch shorting out that switch where it lands on the relay in the passenger well (5-speed with J-shift) as a temporary fix. I was just going to wait until the weather warmed up to swap the switch. I know how to drop the tranny but I find I really like the manual switch. The 4x4 dash indicator tells you if it is engaged. The only thing that could go wrong is thinking you are in 4x4 when you actually have the TC in H2. It's not something I ever remember doing. I finally made the switch pretty instead on leaving it taped to my phone mount.

In the army they say there is nothing more permanent than a temporary installation.