1997 Explorer XLT no 4WD low range

[backroads1]

New to this website. I appreciate the valuable info from all of you to help solve problems on this vehicle.

Original problem: flashing 4WD lights on dash generated 4 trouble codes: P1850 (T case contact plate B ckt), P1854 (T case contact plate C ckt), P1866 (T case svc req'd), P1812 (4WD mode select switch ckt fault).

Attempted remedy #1: wrecking yard t case shift motor with everything cleaned up. Result: 4WD high range OK and dash lights do not flash now. 4WD low range not available (4WD light stays illuminated, but low range not showing on dash and still in high range)

Attempted remedy #2: new t case shift motor. T case selector rotates smoothly by hand. No change from #1 result above.

Attempted remedy #3: new dash mode select switch. No change from #1 result above.

Attempted remedy #4: new relay behind center of dash. No change from #1 result above.

Attempted remedy #5: new GEM put in behind center panel of dash. No change from #1 result above.

All of this work occurred over November and December. I am out of ideas and need some help from the group on what needs repair to get 4WD low range.
Thanks, Don (backroads1)

 

[dogfriend]

Question: Did it used to work? Are you sure that you are following the correct procedure to shift to Low Range? You need to be stopped or moving less than 3 mph and you need to shift the trans to N before moving the switch.

 

[backroads1]

Vehicle at a stop; placed in neutral prior to moving mode selector switch, foot on brake.
All these parameters met.
Started around early Nov 2010 when lights began flashing at start up - 4WD not in use at the time.

 

[dogfriend]

Since you replaced most of the components, I'm guessing that it is a problem with the wiring. I'm attaching the schematics. If you send me a PM with an email address, I can send you the diagnostic routine for No Shift to 4x4 Low.

 

[dogfriend]

This is the list of causes that they give for No Shift to 4x4 Low:

 

[backroads1]

Thanks. I have full workshop manual and have most of the material you sent. Unfortunately, many of the tests require special Ford testing equipment, so have to improvise where possible. I don't think there is anything wrong with circuitry or lamps. One thing I need to check is the 20 amp fuse in the power dist box under hood.
Back to the drawing board - will advise.

 

[dogfriend]

Do you have a scan tool that can read Ford Extended codes? If you can borrow, buy or steal one, you can look at GEM PID's while you try to shift into Low range and see what the GEM thinks is happening.

 

[backroads1]

It was a 20 amp fuse in the power distribution box. Goes into low range now.
I didn't check the easy stuff first, but the trouble codes led me to think other things were wrong.
If fuse blows again, will be searching for short to frame.
On question of extended codes reader, what is the best source to buy one?
Thanks

 

[dogfriend]

Glad you got it fixed.

Not sure on the code reader because the one I bought was discontinued. I bought AutoDiag software that runs on a Palm Pilot. It helped me find a misfire that didn't set a code, but I was able to scan for Misfire True as a PID and tracked it down to the coil pack.

Here is an older thread discussing some different options:

http://www.explorerforum.com/forums/showthread.php?t=147643&highlight=palm

 

[iamsoblank]

Maybe yall can help me out. I have a 98 ranger and my t-case motor went out so i replaced it. But it had the BROWN WIRE connected to it and the t-case so I had to cut it to replace the motor. Now my low rang 4wd wont work but it used to go in and out and sometimes get stuck. My question is, is what wire on the new t-case motor do i hook up the brown wire coming out of my t-case too. I already tried to run it to the brown wire under my driver seat but that didn't work.

 

[dogfriend]

The Brown wire is supposed to connect from the Electric Shift Relay to the Clutch inside the transfer case. The GEM turns the relay on and off to shift between 2wd and 4wd. The Electric Shift Relay is in the relay box under the dash.

This schematic is for a 97 Ranger, the 99 Ranger is the same. I don't have the schematic for 98, but I would expect it to be the same.

 

[iamsoblank]

Yeah I got that but my brown wire isn't connected to anything on my transfer case. It's just hanging there. I need it to be connected to my Transfer case motor like it was before i replaced the motor but i don't know what wire to connect it to. The brown wire on the old motor had it's own place but this one don't.

 

[dogfriend]

The brown wire should come out of the transfer case by itself, then go to the connector that is attached to the shift motor. Instead of cutting the wire to change the shift motor, you are supposed to remove the brown wire from the old shift motor connector and then replace it in the same position in the new shift motor connector. You can take the wire(s) out of the connector by removing the plastic terminal lock (usually a red plastic piece) and then using a pick to release the individual terminal(s).

 

[iamsoblank]

Well dang it!! I guess i'll look at it today and see if there is a place on my new connecter where it goes. Thx for the help.

 

[Tavycal]

Hi all. I have a 1997 Explorer. When in snow today, in 4 wheel auto, my front wheels were not turning. Can someone help? When I switched to 4wheel low the light came on and went out.

 

[glenn_a]

It was a 20 amp fuse in the power distribution box. Goes into low range now.
I didn't check the easy stuff first, but the trouble codes led me to think other things were wrong.
If fuse blows again, will be searching for short to frame.
On question of extended codes reader, what is the best source to buy one?
Thanks

hi there, just reading this thread is very helpful but can i ask where is this 20amp fuse located? please help....thanks!