P1700 #2 speed sensor and missing wiring harness

[Gunner_T4R]

Gents just got me a 96 for a steal with the locking rear diff, of course that didnt come without some issues. Like the absence of the wiring harness that will make you get a CEL P1700 and no 4WD shift lift and I am sure there are other things not working as well... my question I pose to you is does anyone know the name of said harness? I do have the FSM but cannot make out the harness name or P/N.

 

[TheDurk]

You mean the harness that goes to all the plugs on the transmission? That would appear to be the Frame Wire. But that does a whole lot of things. See Part G of the attached from the 1996 Factory EWD. That shows all the harness names and their location.

Are you sure this is the original '96 transmission? I have a suspicion somebody may have put a later A/T and ECM into your '96. This may be why your frame wire is missing some plugs. My '99 FSM has no P1700 (I don't have anything earlier) but it does exist in 2002. Funny.

 

[Gunner_T4R]

thanks man! I am not sure if it is the original trans and its the wiring harness that goes to the trans and transfer case and front diff? it all started with that ETC P1700 then I find that the speed sensor isnt even connected. well what can you do! looks like I got some wiring to figure out or possibly go to the pick and pull and see if I can find that portion of a harness. But it appears that everything in the attached document is what is not connected resulting in no 4WD light and ETC.. I plan to get it on a lift this week to see if the center diff is locking.

 

[Gunner_T4R]

from the information in the FSM I need to locate ED1 ... getting dark here but I will run it down tomorrow in the drive way..

 

[Gunner_T4R]

well I have looked all under the T4R and can find no possible place for another harness to hook in. Can anyone tell me if the 4WD harness is part of the frame wire?? or the motor... I would think the frame and it appears that is how it is shown in the FSM.. if not I might have to rig a switch from the 4WD shifter button to the front diff... dont think it should be too hard just need to get a relay!! thoughts anyone?

 

[TheDurk]

I think part of your problem is your are applying a 2002 FSM to a '96 4Runner. I know little of the evil slushboxes, but I believe '98-'98 never had a center diff or AWD. Just an electric TC to engage 4H (locked, 'cuz no center diff) or 4l and a vacuum system to engage the ADD (front diff.) 2002 has an electric front diff system, totally different and the AWD TC with center diff. Center diff/AWD started with '99 Limiteds.

 

[Gunner_T4R]

that could be my issue! anyone have the 96 FSM?? that would be a BIG help!! anyway I still plan to see if I can activate the solenoids that control the vacuum to the front ADD and run a toggle in the cab. But, I would still love to know if the wiring harness is part of the frame or the engine... Going to the local junkyard tomorrow and see what I can find, they only have a couple of 98's and a 99... but worth a shot... anyway thanks for the help man!!

 

[St Runner]

There is only one wire set from the engine harness on my 97 that attaches to the front diff. It is the same on both the manual and auto engine harness. It runs down the drivers side of the engine and near where the clutch slave is it clips to a short run that goes under the bell housing and clips into the rear bottom of the front diff. I am pretty sure that is the indicator light. I did not know that the 96 had a center diff lock. As has been said it sounds like somebody put a newer trans in. Nobody that I have ever met goes around unplugging a wiring harness for no reason and those plugs might clip together easily but they don't like to come apart!

 

[Gunner_T4R]

the junk yard had 5 4runner all 2WD... the guy at the junk yard said that the 4wd harness is part of the motor loom... so I guess its safe to say that my motor was swapped from a 2wd different year or something... did score some good interior parts and a new fan shroud...anyway... anyone have any ideas about the best way to bypass all the electrical junk and hook a switch to the actuators that controls vacuum for the ADD? or do you think best to just try and swap the entire engine harness with a junk yard special... I am going tomorrow and put it on a lift and apply vacuum to the ADD hoses and see if I can get it to lock up.. wish they made a kit like this for T4R's Alloy USA - Jeep Differential Cable Lock Kit | 4WD.com sure would make life easier...

 

[Gunner_T4R]

3 way switch at the VSV maybe?

 

[TheDurk]

An SPDT switch to flip 12V+ between the brown side and the blue side of the VSV's should work just fine. Is the twin VSV assembly there on the driver fender wall with the hoses going to the front diff? Each valve would need its second terminal connected to ground.

The diagram you posted is for the J-shift. Is that what you have? If so, you could always add the relay and wiring to the TC later.

Is there any wire connected to the front diff? You would just need to add a key on 12V+ and a wire back to the gauge cluster to get a 4WD indicator. It would not be a true 4wd indicator, only a front diff indicator, but it is better than nothing. To get a true 4wd indicator, you would need to wire in the switch on the TC and add the relay, again, assuming you have the J-shift.

On the other hand, if you have a push-button 4wd switch on your auto shift lever, the subject gets a lot more complicated. Please let me know which you have, j-shift or push-button, and I'll post your circuit schematic.

 

[Gunner_T4R]

I posted the wrong schematic, and yes i have thepush button on the shifter.

 

[St Runner]

Did you run the vin number for the 96 to find out how it came from the factory?

 

[Gunner_T4R]

No, I havent.. I think I am beyond that now.. the way I see it is I have two options either acquire a engine wiring harness for a 4WD or figure out a way to electrically engage the 4WD like Turk suggested.

make sure my understanding of the 96 T4R is correct? it engages itself just like a dana 30 on a yj via vacuum? and not electrically? so if that is the case I should just be able to do SPDT switch...right!! the only thing I can see on the front differential is this plug but have no idea what it does? I am assuming that it provides the logic for the 4WD ECU.... and then I have taken a picture of the VSV on the fender...