4wd vacuum system [pure novice confusion]

It's going to be the switch on the transfer case with the Black/Yellow & White/Black wires going to it, that's what tells the relay that it's in 4wd so it locks the ADD.

 

Okay sick man I’m gonna go hunt for it RN and make sure it’s plugged in. Do you know off the top of your head how I can test it to make sure it works ?

 

Came here because your truck looks awesome!

Good luck with the hoses, i have no clue on that part

 

The switch should be closed when the button is pushed in and open when it is released.

 

turns out the 2003 with a J shift and NO 4wd BUTTON, doesn’t use vacuum systems for 4wd!! The hoses ended up just being a venting system to get moisture out of ADD!!

and thank you man!!

 

Ahh my truck doesn’t have the 4wd button on the shifter !!

 

No I meant the button on the end of the switch that screws into the transfer case.

 

I’m wondering if I don’t have a transfer case switch because my truck doesn’t have the 4wd button ?

 

Okay sick I’m about to go find it appreciate the insight a lot man. Doing work on the truck is definitely kind of fun even though it’s shitty circumstances but I’ll feel awesome when we’ve fixed it and I’m blasting through glamis

 

The neutral, low range, and 4wd detection switches are still on the transfer case to tell the PCM, ADD relay, and indicator lights what position the transfer case is in.
The button your referring to is the 4wd select button, that system adds an electronic actuator to the transfer case that shifts it into and out of 4wd in addition the the ADD actuator.

 

Where physically on the tcase is this switch located im having a difficult time finding it. I tried googling and YouTube but can’t find out where it is

 

This is the best I can come up with, looks like it's on the top passenger side of the transfer case.

 

From what I’m reading I don’t think mine has those D:

 

https://www.tacomaworld.com/threads/1st-gen-transfer-case-identifcation-for-replacement-swap.753707/

 

Do you have a J-shifter?
If so, read the text by the arrow.

 

he specified J-shift on first page

 

it's the 4WD sensor (84222-35110)

"Actuator" in this instance is the "button" on the non-J-shift versions

dumb terminology IMO

 

also @EvanDykesOlYeller you may want to get the rear wheels off the ground and try "rolling" the drivetrain forward.

even with mine sitting still in Neutral my 4WD does not engage. I have to roll forward or reverse slightly to get the forks to "engage" in the transfer case

once that happens I hear the sequence and the front diff then engages. but the front will not engage unless the transfer case has already engaged, hence the sensor.

I'm not sure the voltage/resistance/whatever but it could be possible to send power to the front along that wire (yellow/blk) but could ultimately damage the sensor itself (PSA: I'm no electrician )