4x4 Control

[Fordboy77']

I am just throwing this out there, to see if anyone has any ideas why the ranger won't go into 4wd. I have replaced the shift motor( previous owner/mechanic told me thats what was wrong with it) and turns out that its not the shift motor. From what i know about the early electronic 4x4 used in rangers and explorers is that your supposed to hear a clicking sound coming from the Control Box in the back seat. Well i can push the buttons, and get nothing at all. When i start the truck up with the 4x4 computer disconnected the 4x4 lights on the switch do not come on. But when i start the truck with it connected the 4x4 lights come on for a second. So it seems to me i have power to the switch, but not to the shift motor or to the control box? There is also an LED test light on the computer, and i have never gotten one to come on. Anyone have any thoughts on this? Oh and i have only tried replacement computers out of exploders out of the junk yard, non of which have worked. The new computer cost around $330 or so, so i am trying hard to avoid it. Also i have my neutral safety switch bypassed(done by last owner), so the computer thinks i am in N, and can start the truck in gear, could that cause any of this? I've been fine driving around in 2wd since i bought it in june, but it'd be kinda nice to fix the 4x4 just to have it.

1991 Ford Ranger XLT
4.0l V6
5 Spd
The computer part # is
Motorcraft F17B-7E453-AA
Thats one out of an exploder, but the one that was in my ranger when i bought it has the same number.
Evil Little Black Box

 

[CraigK]

Fordboy

Not likely this will help you like it did me (same sypmtoms - no light, no shift when buttons pushed), but you might consider trying this . . .

I simply went underneath the vehicle and disconnected and removed the shifter motor. I cleaned all the connectors with aerosol contact cleaner, and then I also slightly sanded (to increase electrical contact) the area between the bolt holding the shifter bracket tab at the end of the shifter motor to the T-case. I then reinstalled the shifter motor. Whole thing took maybe 45 minutes, zero cost. It has worked like a charm ever since. (bad connection or ground???)

There is also an extensive writeup in the Tech Section here on how to remove and disassemble the shifter motor and clean worn brushes/contacts, apparently a common issue. I was going to do this, but simply didn't have to.
Good Luck.

CraigK

 

[trusted_expert]

i think i rebuilt my shift motor 4 times and replaced the computer once before giving up on it. i just ended up picking up a manual 1354 and swapping that in. 1000 times more reliable probably one my best mods to date.

 

[SAY789]

any updates on this? my 94 is doin exact same but when key is off the module led is on and when key is on it turns off. And reset button makes led brioghter when key is off