4x4 issue

[HighMiler]

Hello everybody, I've been registered for a while, but never posted since I was able to find the solutions to my problems from other posts, but this one has got me stumped.

I have a 2000 XLT Expedition, 4x4 (obviously from the title) w/ 283k miles. It's been a champ of a vehicle, but I have thrown quite a bit of money into it (other than gas). I just yanked out my heater core (thing was completely shot) and put the new one in. I have everything back in place and reconnected (as far as I know). I started it up and the core worked perfectly (no mist, no odor). The instrument panel, lights, brakes, windows, horn and everything works, except for the 4x4. With it in A4wd, the 4x4 light flashes on and off constantly. Once turning it to 4-low or 4-high, the light goes off and nothing engages, but the light stops flashing. Before I changed the heater core, it worked perfectly. So, is there any place in particular that I need to check out? I hope to God I don't have to yank everything out again. Any help will be nice!

 

[Bedrck47]

Before I changed the heater core, it worked perfectly. So, is there any place in particular that I need to check out? I hope to God I don't have to yank everything out again. Any help will be nice!

I would say that you have answered your own question as it appears you missed something when you re-assembled the dash.
Could be that a pin got dislodged when you reconnected a connector

you could remove the radio and check the transfer case relays and connectors or remove the panel on the dash above the glove box to gain access to any connectors in that area
check to see if any pins got pushed out of the connectors

 

[jlo82585]

make sure to re check all your connectors, I have seen many many times connectors that were plugged in but not snapped together, they may look connected but if you can pull them apart without depressing tabs and such, its not making a good connection. I would also check the wires to make sure nothing got broken, anywhere the wire makes a 90 degree or more turn or is up against something hard is a possible break point. I just saw a brand new freightliner come into our shop yesterday with 500 miles on it and the main body harness had already rubbed through and killed the ABS. It happens more frequently than you may think.