98 Mazda B3000 SE V6 4wd auto transmission auto lock hubs. Four low and high flash the same six times as all the others. I have tried to study all the threads and fix myself. I have;

changed the vacuum lines all the way to the metal stud at wheel

changed dash switch from donor truck at junkyard

new not refurb transfer case motor

new solenoid that’s in front of number passenger side. Vacuum line goes in, out to splitter to hubs

changed the module in front of the GEM from different junkyard donor

checked all fuses i know to check that owners manual manual says has anything to do with 4wd

still have flashing lights. Hear no sound from transfer case motor. Don’t hear it trying to do anything. Contact cleaner all the connections.

My thought is to change auto hubs to manual. Is this the logical choice? Have I missed something I need to go back and check or change?

Great running truck. 203000 miles and fires right up. Shifts fairly smoothly.A/C didn’t blow out vents when bought. Found the melted vacuum line, repaired and now can hang meat. Vacuum line to solenoid was missing when purchased. Previous owner great friend of family. “All works as far as I know”. For price I pAid was ok if need some things.
Anxiously awaiting any and all help.

 

1998 Ranger has PVH(pulse vacuum locking hubs) but won't effect 4WD lights either way, but good it was refurbished.

The Flashing 4WD light means that the contacts/sensors on the shift motor are not moving when GEM(4x4 controller) activates the 4x4 relay box which sends the shift motor 12volt/ground

The 4WD dash switches never break on these, just 3 resistors inside, maybe if you hit with a hammer, lol, otherwise leave them be, its never the problem

GEM(generic electronic module) is behind the radio, its the Body Computer, runs all the cab electric, i.e. wipers, door locks, windows, ect...........and 4x4 system
4x4 relay box is behind GEM

Fuse for the shift motor is in engine bay fuse box, fuse #3 20 amp

If fuse #3 in engine bay is OK then next stop will be GEM and relay box, assuming you have checked the shift motors connection

 

Would GEM go bad for 4wd only? Everything else works perfectly. No auto lock or windows. But wipers, blinker, warning lights etc. work.

 

Of course it could, but more likely the relay box if fuse is OK and you have tested shift motor


And just a heads up about "new" parts, new just means NEVER TESTED or LOOKED AT, so you are the first to test that new part, its "likely" to work, but may not so test new parts

 

By relay box your talking about this part?

 

Yes, that has 2 relays inside, and is hooked to the fuse in engine bay and to GEM

One 5 pin relay for each wire to the shift motor, 2 wires so 2 relays
Each relay Grounds its shift motor wire when "off"

The shift motor is the same as a power window motor, send it 12v/ground it turns clockwise, send it ground/12v and it turns counter-clockwise, window up/window down, transfer case 2WD to 4high/4high to 2WD

The GEM activates one relay based on the direction it wants transfer case shift rod to turn
That relay sends 12v on its wire so shift motor now has 12v and ground(other relay) and turns

GEM then watches the contacts inside shift motor open and close, and opens relay(turns off shift motor) when contacts match the selected position
If the contacts do not change then GEM will flash the 4WD lights on the dash to let driver know something is wrong

Contacts seen here: https://www.explorerforum.com/forums...-motor.123542/

Pictures 5 and 6

 

Little update.
Decided today I would look at all the fuses that have anything to do with GEM and 4wd, take them out, inspect, clean with contact cleaner and put back. I still have no 4wd. Take out dash, take out GEM and transfer case motor module, spray all connections and wipe clean. Put all back together and boom, 4wd works. Didn’t clean module when I installed from junker. So either it was culprit or GEM connections. Either way it works. Factory hubs working. All is well. On to the next project in another thread. Thanks for all the help!!!

 

Good work

Thanks for the update and the FIX