I've been searching for days, and am currently going through this guide ( http://ylobronc.users.superford.org/...6/elec1356.htm and http://www.forddriver.ru/storage/51.pdf ). My issue is that I have no 4 Low. 4 high activates as soon as I press the switch (audible click heard from the module and both lights activate). When I press 4 Low, there is no audible click heard, and no light comes on.

I have continuity at the speed sensor and MLPS, so those pass. One wierd thing is that the 4x4 Control Module self-test light does not come on. Key in and in the on position, key off, etc... I press the button, and no light. I would say the Control Module is bad, but it still goes in 4x4 High without issue. Is it more likely that it's a bad LED and a good module, or a bad 4 Low portition of the module?

Any other tests to verify bad module? I'm stumped

 

what year is the truck...My 1992 has to be in neutral and 4x4 to get low...same for taking it out...

If you don't follow the correct procedure it won't go to Low...

same for getting out of low.

bests

 

How are you attempting to engage 4 low ? You can’t just turn the switch like 4Hi...

 

To anybody that comes across this issue, it was the 4x4 module. Replaced it and all was good. And yes, 4-Low activates at a stop in neutral upon activating 4-High

 

Read this caption:


(phone app link)