4X4 low light flashes

[RangerJ]

1994 Ranger XLT 4x4 manual,4.0. I replaced the 4x4 control module from a salvage yard and it worked well several times but this morning when I started the truck the 4x4 low light was on the dash switch but the 4x4 was not engaged so after pressing the switch a few times the light went off. I then tried to engage 4 low and the light just flashes ,but I have 4 high.

Is this a sign of a bad control module ,dash switch, or some other issue?

Any advice,tips are welcome.Thanks

 

[RonD]

Good 4WD troubleshooting guide here: http://www.therangerstation.com/tech_library/transfercasetroubleshooting.htm

1994 and older or 1995 and newer

Flashing light only for 4lo would mean the shift motor didn't rotate enough to engage 4lo, or didn't rotate at all because the module didn't get Neutral signal(clutch pedal in, or automatic in Neutral), or Brake light signal(foot on the brake pedal)
4lo requires these parameters to engage, 4hi doesn't("shift on the fly")

 

[RangerJ]

Thanks RonD, I will check These things

 

[carfox]

on GM trucks a flashing light would indicate that the front 4x4 differential solenoid has failed and your 4x4 capability, with it.
since there is noting to "lock" the differential with.

you need a new 4x4 actuator?

 

[RangerJ]

Just noticed that I forgot to update my post. I replaced the 4x4 control module and the problem was solved.

 

[RonD]

Thanks for the update

And good work