4wd electrical issue

[vrt93]

Here's one for the drivetrain gurus; I've been having an issue where 4wd will engage when unlocking the truck after its cooled down or when slowly going over a speed bump (5-10 mph) but the light wont come on. I know it engages because I can either hear it when i unlock the truck, or turning on paved surfaces suddenly becomes very difficult and jerky after a speed bump. In both instances, I can shift to 4wd low and then back to 2wd and I'm good to go. I also have the 4wd light flash sometimes when I hit small bumps on the freeway, but that doesn't always result in 4wd actually being engaged. Does anyone know what's going on? I've heard everything from a chafed wire to a TIPM connector to a bad 4wd shift motor. Just trying to narrow it down

 

[Ozymandias]

I would say 4WD switch, rarely they fail and do funny things. Mine was replaced just prior I bought my truck with 130K on the counter.
Since then, knock on wood, works perfect. I got a spare in my boony box.

Oh forget, when you open the truck that triggers a wake up call to all modules in the truck. That's probably the reason for yours behaving weird.