Trying to get 4wd working for a customer. I replaced the tcase motor and no change. Swapped ina. Good switch and control module and still not working. I have no lights on the switches. I checked all electrical have good ground and power to module but module isnt sending 12 volts to switch or tcase motor. I get 4.5v to switch and 6.7v to motor. Same results with either module I have. Not sure where to go from here.

 

Welcome to the forum

1993 4x4 wiring below

This system was used thru 1994, in 1995 a different system was used and in 2001 another different system, just FYI

But the shift motor was the same on all years, FYI

Controller was different, good article to read on your 1993 here: https://www.therangerstation.com/tec...is-1994-older/
In that article is this
After checking fuses do that, checking a fuse doesn't mean looking at it, swap it out or use an ohm meter to test it

You can get corrosion on under side of engine fuse box, lowing voltage at controller
Measure battery voltage, then any wiring test should be the SAME as battery voltage

 

Ya thays the article that I followed to diag the truck. Like I said I have 12v to the module. But it's not sending 12 volts to the tcase motor or the switch. That's why we got a replacement module but nothing changed. Including the amount of voltage the module is sending to the switch and motor.

 

And you did the push button test?
And module passed

The way the system works is fairly straight forward
Inside the module are 2 relays, 5 pin, one relay for each motor wire
Both relays pass a ground to each motor wire when relays are off, so each motor wire is grounded
The controller just needs to activate 1 relay, which cuts the ground and connects to 12v on that 1 wire so shift motor turns clockwise
If controller activates other relay then motor turns counter clockwise

So test if both motor wires show as Grounds with key on, they should
And when you change switch position you should HEAR 1 relay "click" closed

I never test the switch wiring but its a 3 wire toggle switch
So with OHM meter test if wires are connected, unplug the connector at the controller there are 3 wires
white/blue wire
orange/blue wire
blue wire

Should be no connection between all 3 wires in 2WD
Push button for 4high
white wire should now show 0 ohms(connection) to either the orange or blue wire, but just one
Then try 4low opposite wire should now be connected to white wire
If you are not getting connections as described above then wires or switch is bad

I don't know if this is a Voltage switch, doesn't need to be, could be a Ground switch, i.e. white wire could just be a ground, and if orange and blue wires are not grounded then 2WD, if either IS grounded via white wire then 4high or 4low
Or could be a voltage switch, works either way


The other 5 wires to shift motor are position wires, controller needs these to "know" where it is, and which way to turn the shift motor when switch is used
If the controller doesn't "see" a valid "position" then it wouldn't respond to any switch commands, because its "lost"
So with key on controller looks for "position" of shift motor, if it doesn't "see" a valid position it should flash BOTH 4WD lights for a few seconds indicating its "lost"
But not always

OPEN = no connection between wires
SHORT = 0 OHMS so connection between the 2 wires