1997 Explorer XLT no 4x4 low range

[backroads]

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). All trouble codes removed except P1812.

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. No trouble codes showing.

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 (backroads)

 

[swynx]

does it make noises when u try and put it in 4 low? theres a deal that used to tell my 4wd that it was moving to fast to engage 4low so it wouldnt. there is info on this in the tech section.

 

[feellnfroggy]

First thing stop buying stuff. start diagnosing what you already have and narrow down the problem. If you hae replaced pretty much every part start looking at how your locking in. You must be

stopped
in neutral
in 4hi
foot on brake if auto
foot on brake/clutch if manual

If it still dont shift into 4lo then try reversing for 4 feet as to relieve stress from the driveline then follow the steps again.

if still no good then perform the steps above, shut the truck off turn it back on and turn it straight to 4lo.

Read the tech section on all possible fixes before sinking any more money into parts. check all fuses and relays.

 

[backroads]

It was a 20 amp fuse. Runs OK for now.
If blows again, will need to seaech for short to frame.
Thanks