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My 4WD slowly stopped working over the past few months. Went from switching occasionaly to not switching (just clicks) to no clicks at all. The lights flash 6 times every few minutes. Removed the xfer case motor and found the magnets in the motor crumbled into pieces. Figuring that was the problem (definately one problem), replaced motor. Now it still doesn't work. I don't hear any relay click. I pulled the dash switch off and ohmed it out. Continuity on pins 1 and 4 and 2 and 3 in all swith positions. Doesn't seem to be any differences between any of the switch positions. Anyone with more electrical knowledge than me think this means a bad switch? I am getting power to the switch since i checked the wires going in. The fuses are all OK. Also, can anyone tell me where the control module is? Nothing behind the jump seats like I've heard.
Any help with my troubleshooting would greatly be appreciated.
Unlike earlier generation 4x4 Rangers, the dash switch/light is not an accurate indicator of whether or not 4x4 system has engaged properly on your '98 Ranger. I wouldn't focus so much there as I would on the GEM and transfer case itself.
Here is a little background on how the '98 4x4 engagement system works:
....The ['98-'00 Ranger PVH] four wheel drive system is an electronic shift 4X4 system that allows the operator to choose between three different modes. The operator can switch 4X4 HIGH modes at any speed. To engage or disengage 4X4 LOW the vehicle speed must be less than 5 kph (3 mph), the brake depressed, and the transmission must be in NEUTRAL.
The shift motor sense plate, an integral part of the electronic shift motor, informs the generic electronic module (GEM) of the transfer case shift motor and contact plates A, B, C and D position.
The digital transmission range (TR) sensor is located on the LH side of the transmission, and informs the GEM when the transmission is in the NEUTRAL position.
The electronic shift motor is mounted externally at the rear of the transfer case. It drives a rotary cam which moves the mode fork and range fork within the transfer case between the 4X4 HIGH, 4X4 LOW and 2WD range positions.
When the GEM verifies the completion of the transfer case shift from 2WD to 4X4 HIGH (reading the contact plate positions), the GEM will then energize both pulse vacuum hublock (PVH) solenoids (supplying ground for 45 seconds). The PVH solenoid will allow a HIGH flow of intake manifold vacuum to the "wheel end hublocks", engaging the wheel end hubs to the front differential and transfer case to achieve four wheel drive.
When the GEM verifies the completion of the transfer case shift from 4X4 HIGH to 2WD (reading the contact plate positions), the GEM will then energize only one (low vacuum solenoid) of the PVH solenoids (supplying a ground for 10 seconds). The PVH solenoid will allow a "LOW" flow of intake manifold vacuum to the wheel end vacuum hublocks, disengaging the wheel end hubs from the front differential and transfer case to achieve two wheel drive.
The 4X4 shift motor uses a module containing two relays which, under control of the GEM, shifts the transfer case shift motor between 4X4 HIGH, 4X4 LOW and 2WD modes.
The solid state clutch relay is used to activate the clutch within the transfer case which aids in shifting to 4X4.
Forgot to mention one other thing. I activated the switch with the new motor taken off of the transfer case. The motor did not activate. There are a number of wires on the harness going to the motor and I'm not sure which ones to check for power
There is a 20A fuse in the engine compartment Power Distribution Box for the Electronic Shift Relay and Electronic Shift Control Module, did you check that fuse?
Also, my manual indicates that there should be a Yellow (Pin 4) wire which is your 4WD Motor feed, and an Orange (Pin 7) wire which is your 4WD Motor return, in the harness connector going to the transfer case assembly. You should have close to battery voltage there when testing.
The Electronic Shift Control Module is behind the instrument panel, pretty much dead center. The Relay Box containing the Electronic Shift Relay is in the same area.
at your switch you should have 3900 ohms (2) centre contacts in the 2 wheel
position, 1100 ohms in the 4 wheel hi position, and 380 ohms in the 4 wheel low position, I have a 95 and having the same trouble, there are 4 places that power comes from the wiring iam quite sure is the same....the easiest way, by get togeather by e -mail or phone and im sure we can help each other!
Fianlly got it working. I was going to check for power at the motorbut I was curious to see if I could test the GEM. I removed the two bottom connectors on the GEM, plugged them back in now everything works perfectly. Thanks to everyone for the comments and knowledge. By the way, does anyone think the armature in the motor could break into pieces by tapping the motor with a hammer. That was what I found when I took the original motor off. I used a small finish nail hammer and tapped VERY lightly.
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