No 4x4 Low Indicator, No Actuator Movement 97 Expy

[tinkering]

The solenoid mounted on the passenger side of the transfer case is not energizing when switching through the selector knob. There is no 4x4 Low illuminating on the dash, just 2 wheel, Auto, and 4x4.
Is that solenoid for 4x4 low?
If so, I will put the test light on the connector while the selector knob is in 4x4 Low.
What should I learn here?

 

[tinkering]

ATTENTION!!!!
I RE-WROTE MY ORIGINAL POST; MY DESCRIPTION WAS WAY OFF:

The vacuum powered '4x4 front wheel actuator' mounted on the passenger side of the transfer case is not moving when switching through the mode selector knob. I can hear sounds coming from the transfer case when going between modes except into 4x4 Low. There is no 4x4 Low indicator illuminating on the dash, only 4 Auto, and 4x4.
Can that actuator effect 4x4 low engagement?
I need to check vacuum at the fitting anyway; that actuator needs to move through it's full travel of approximately 3/4".
What should I be learning here?

 

[tinkering]

If there is indeed a dash light indicator for 4 Low it could just be a burned out bulb. All of the dashlights are bulbs. It's not too bad of a job to pull the necessary pieces of dash off to access the many bulbs back up in there. There are a number of UTube vids on this subject. Not a bad idea to go to pick a part to grab a couple of those solenoids either.

 

[AZShawn]

Are you in neutral when moving the switch to 4Low? That seems obvious, but I've made that mistake before - the truck will allow you to switch to 4x4 while in gear, but 4LO specifically you must be in neutral for it to work.
You mentioned the bulbs. My '99 has a 'LOW RANGE' light that comes on in the same area as the 4x4 light. There is a pretty noticeable CLUNK when the transfer case goes into low range, so if you're not getting the clunk and no indicator light then my guess is that it is not switching to low.
I hadn't tried to use the 4WD in mine for a couple years, then after deciding to make this my camping/exploring rig I tried the 4WD switch and couldn't get it to work. Ended up replacing the shift motor and it's been working ever since. Don't want to suggest you throw parts at it as maybe the shift motor is fine on yours, but they're known to fail if they're not used regularly. Hope you get it figured out!

 

[tinkering]

Are you in neutral when moving the switch to 4Low? That seems obvious, but I've made that mistake before - the truck will allow you to switch to 4x4 while in gear, but 4LO specifically you must be in neutral for it to work.
You mentioned the bulbs. My '99 has a 'LOW RANGE' light that comes on in the same area as the 4x4 light. There is a pretty noticeable CLUNK when the transfer case goes into low range, so if you're not getting the clunk and no indicator light then my guess is that it is not switching to low.
I hadn't tried to use the 4WD in mine for a couple years, then after deciding to make this my camping/exploring rig I tried the 4WD switch and couldn't get it to work. Ended up replacing the shift motor and it's been working ever since. Don't want to suggest you throw parts at it as maybe the shift motor is fine on yours, but they're known to fail if they're not used regularly. Hope you get it figured out!

That's great info AZShawn. Thanks.
I have tried to put it in 4Low while in neutral and park and everywhere. I tested it in the winter where I got stuck in a drift and saw the front wheels turning but there was no low range dash light illuminated. I suppose it might have stayed in 4Hi?
Where is the shift motor; is it a big job? I found a solenoid under there.
Thanks

 

[tinkering]

I found a Utube vid by 1A.com that covers the location and replacement of the shift motor, pretty simple.

 

[AZShawn]

Yep, I think I used the same thing. It was pretty simple. The hardest/most annoying part is re-pinning the harness, but as long as you get that right it is pretty straightforward.

 

[tinkering]

That's right. Thanks. I'm going to grab a shift motor or two from the wreckers when I go for some other parts.

 

[tinkering]

The LOW RANGE bulb was indeed burned out along with some others. I changed the GEM and fusebox (wreckers unit, same part number) in hopes that the LOW RANGE problem might be related. The 'auto doorlock on driveaway' feature was intermittent so could have also been fusebox GEM caused. There was green corrosion buildup visible on the old fusebox circuit board, so I cleaned all the terminals on the replacement units, with electronic parts cleaner spray.

The transfer case is switching to LOW RANGE now, as long as the tranny is in Neutral. I'm not sure if it is due to the GEM or fusebox replacement but I'm happy.

 

[tinkering]

I forgot to put a bunch of dielectric grease into the fusebox and GEM connectors before I installed it. There is definitely water getting into that area most likely attributed to the very common problem on these and F150s of the windshield seal leaking.
Is it worth pulling that whole fuse box /GEM unit out again just to apply some dielectric grease in there?
I am growing weary