1999 4WD
Can someone tell me If the rotation of the Transfer case shifting Motor has the electrical connection to tell the light on the Dash board to change from 2WD to 4WD?

The light does change as it should but I do not think it is shifting into 4WD. IF the rotation of the shifter motor directlyaffects the light turning on, thenwhat would be further down the line that would cause the transfer case not to engage?

I heard about some solenoid, is that after the transfer case motor? Not familiar with these Half shaft type 4WD's.

 

More than likely, your transfer case is engaging properly. It is likely that the front axle is not engaging. The actuator for the front axle is located under the battery tray. Check for vacuum at the actuator when the transfer case is in 4wd.

Do you have the Auto4wd option?

 

Auto4WD???

It is the three button setup. So I would say No.

I found a short hose Behind the ABS that I am guessing disconnected from the Low Vacuum Sphere(from what I read). I plugged that because , honestly, I can't even see where the sphere is. At the same 'T' area I see a hard vacuum line head toward the front headlight / Battery tray. I guess that's where I looking for the actuator. Way too much stuff there, does the tray have to come out? I guess I can check vacuum at the 'T' behind the ABSinstead of digging..no?

Ahh, I just looked up in NAPA; the Light switch is in the Transfer case so the T Casemust beshifting.
I just can't find a picture of what this actuator looks like for the axle .I find an "Axle vacuum lock out switch".. I can't tell if it'sa vacuum switch orelectrical..

 

You have a vacuum switch on the transfer case which will send engine vacuum to the front axle actuator. All you need to do to figure out what the actuator looks like is remove your battery & battery tray. If you have vacuum to the actuator when 4wd is selected with the engine running, then you need to determine #1 if the vacuum is appropriate (i.e. close to engine vacuum level), #2 that the actuator is pulling on the cable (not a busted actuator diaphragm), & #3 that the cable is actually moving and pulling to the appropriate distance.

#1 you need a vacuum gauge for
#2 you can use a vacuum gauge to check as well by putting it inline with the actuator, then clamping off the vacuum supply line. If the pressure rises to atmospheric, then the actuator itself is bad.
#3 you can check with a pair of vice grips by clamping on to the end of the cable and pull it by hand.

 

Got it.

Vacuum from Intake Manifold to Switch on transfer case, when shifted to 4WD, switch opens and lets vacuum continue to actuator.

I see what the actuator looks like from a Pic. It doesn't show what sticks out the bottom of the actuator. So i don't see this cable you mentioned,I'm guessing that sits on the end of the actuator and pulls up as vacuum is applied to engage the axles?
When I can eyeball it, I will understand better.

 

Daughter came home this evening, climbed under to take a look. I see the cable coming from the buried actuator going to the Front Diff. Right where it enters the diff there is an electrical connection. what does that do for a living? I thought the '4WD' dashboard light was triggered from the transfer case. Yes?
I see the three vacuum lines going into the Transfer case switch too. pulled out the connector and back in just to make sure it was seated well. I see it has a keying hole in it.
Don't have daylight or warm enough to start pulling out the battery tray to do some vacuum tests.

 

The light is controlled by the TCCM, which uses the switch in the front axle as an input.

 

So that's really confusing. If the light on the dash is activated by the movement of the actuator 'wire' at the Front axle. then why is the light happy but no 4WD?

Don't answer this, I gotta get all 4 wheels up in the air and and put it in 4WD and see where the missing link is. Start off by seeing If the driveshaft is turning.
There obviously has to be oil in that front diff so pulling off the cover plate where the cable goes in would be a messy venture. does that diff take standard 80/90 gear oil?
Thanks for sticking with me so far

 

The car was home for a while today. Put it up off the ground.

Put in 4WD. light comes on, Transfer case engages causing front Driveshaft to rotate. So I have to believe that if the Dash light is triggered right at the Front Diff where the actuator cable goes in then the cable must be disconnected from whatever it's supposed to be pulling.

I cannot find a diagram of what this cable does inside the Diff.