Electronics Suck

[Fordguy77]

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?

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
https://mail.google.com/mail/?ui=2&ik=7c715b5f00&view=att&th=127274e6764bb339&attid=0.1&disp=emb&zw

[gm4x4lover]

I know you just replaced it but it sounds like a bad shift motor. I think the neutral saftey is purely a signal interrupter, on a standard tranny it doesnt need to know what gear you are in so that shouldnt have anything to do with it. I had really bad luck with the shift motors on my 94 explorer. A junk yard one is what fixed my problem.

[1freaky1]

On the early Rangers I am not sure if they used relays also like on the 93 and newer models. On the newer ones it is behind the glove box and with out it there is no power to the motor or computer.

[JeffX]

Is there a manual lever conversion? That should get rid of the problem altogether. As far as I know there are sensors, a relay, a computer and motor(s) involved in these systems. The new Xterras have push-button systems, too. Expensive to troubleshoot if they break.

[Andrew]

That clicking sound may be a relay, so there may be a bad relay in there? Not sure.

But yeah I hate electronic stuff. Give me a manual shifter any day.

[Fordguy77]

No luck on getting anything to work. i have 3 ECUs that i all tested and came back bad, i believe there is something probably bad in the wiring and i really have no desire to chase it down. I am gonna bite the bullet and go to a manual conversion. I'll be going to the junk yard to snag me a new transfer case most likely next weekend, anyone wanting to go?