Ford Repair: 4WH and 4WL lights flashing 6 times, ford ranger, trouble code

Question
I have a 1999 Ford Ranger.  The 4 wheel high and low lights flash 6 times every two minutes.  My 4 wheel drive does not work.  I have replaced rear sensor and GEM module.  The truck worked both times after repair for a short time.  

Answer
Janet,

It sounds like the GEM module has set a trouble code and uses the lights to blink the code out. I will look up if the 6 flashes have meaning and try to get back to you. I will be gone 1-18 through 1-22 so it may be after I get back before I can answer you.