Intermittent battery drain / 4x4 motor/actuator

[snowmad]

Hi!
I’m having an intermittent battery drain problem.
It occurs when the -90 4.0 automatic Ranger has been run in 4x4 mode (with or whit out low range) and then is parked and left some days with the 4x4 button just being disengaged (no indicator light on at dashboard switch)
Most of the times this occur is when wife or someone has borrowed the Ranger but now and then it happens to me to..
I do believe it’s the “2-4-low” actuator on the transfer case that is trying to get out of 4x4 mode.
-That, on those occasions, the 4x4 mode is still engaged even do the light is out and the motor/actuator is trying to disengage until it manages or (most often as the Ranges is sitting still) the battery is drained/dead.
Ones or twice I have heard what I believe is the engine/actuator making “notice” even thou the ignition is “off” and the ignition key is far from the car.
I know the simple solution is to leave the Ranger still in 4x4 more or make sure it is “back” in 2wd mode.
BUT the idiot proof way is to make sure that this “2-4-low” engine/actuator (and control unit?) is powered off and not draining the battery as soon as the key is off ...
-That can be solved by adding a 12v “key on” power relay to the circuit …
So question here is where is the easiest way to “hack” the power supply to these parts located?
I don’t have a wiring diagram(s) or like a shop manual with “electrical wiring layout pictures”
So if I’m to solve this without some help from fellow “Ranger fellows” I’m so lost...
Lars

 

[Dirtman]

Do this...

 

[snowmad]

Been there did that!
I know that "2-4-low"" actuator/motor is the thing intermitent draining the battery.
And now, after some searching on this exelent site i found out that the "2-4-low" control unit is a "power in run or start" unit
I found the wiring diagrams
But the actuator/motor got "aways power" with a 40amp fuse in the circuit.
A relay "hached" in that circuit and wred to be activated in "run or start" will be the solution to my problem.
I recon that 40A fuse is in the engine bay, right side in the fuse box behind the battery.

 

[Josh B]

That little motor takes a 40 amp fuse?

 

[Josh B]

Does it have auto hubs or manual. Do the manual ones require backing up/reversing direction after switching it off to get full disengagement?

 

[Dirtman]

If its draining the battery then something is physically wrong or shorted... instead of adding more components to the circuit why dont you figure out what's actually wrong with it?

 

[snowmad]

Thing is that it's basically a user error not a car error!
It got auto hubs so they need backup / straight reverse drive to disengage. Hard to do when “you” already parked when pushing the button..
40A fuse yes, but I haven't yet done the (re)wiring (waiting for spring) so I don't know what else is feed by that fuse...
This is not a new problem, first time it happened was 1990 and car was still under warranty... ….according to first owner (my dad)
And back then the Ford people explained told him "the who and why" but not a warranty so he added a battery kill switch…
But that takes the adaption out of the fuel injection ecu so I will not use that solution any more.
So ad a relay fix it is for me!