I’ve tried searching the forums but cannot find anything to help on where to start. 2006 H3 with adventure package, 198k miles. When you turn the key on the rear diff lock light starts blinking and then the serv 4wd light comes on when it stops blinking. I’ve tried unplugging it and checking the resistance of the rear coil and got 3.5ohms. All fuses are good and the rear diff lock is never used. Wires leading up above the fuel cell look good. Transfer case shifts fine but will not lock the rear when in 4low the light only flashes. Anybody have an idea where to start before I start throwing parts at it?

 

Somebody "moderated" your thread (hid it from view) for what/why I have no idea, should not have been done.......... so I approved it.

1) scan for any hidden codes using a capable scanner, not a cheap code reader.
2) clean the Transfer Case control buttons, they get goobered up with spills, dust and who knows what. If they stick and or do not make proper contact, that can cause problems.
3) you may have a T Case shift fork problem as a stock Adventure Rear Locker can only engage when the power control modules can confirm the T Case is locked in Low so do the easy stuff first, check the wiring and connectors to the T Case Shift Actuator motor, clean the connectors with electronic cleaner spray.

Side note..... when was the last time the T Case fluid was changed? Rear Diff fluid?

Welcome to HF.

 

What has me puzzled is that the 4wd or locker isn’t being used and hasn’t been used for about a month. This seems to be some sort of self check at startup. I’ll have to work on finding a code, I’ve checked the buttons and even unplugged and reseated the connector with no luck. The fluid part came to mind, I bought this in late July and haven’t gotten around to changing anything besides the engine oil and radiator because it was cracked. The transmission fluid hasn’t been changed, it’s dirty but isn’t burnt, so I don’t really want to change it. With 200k on a 4l60 I probably wouldn’t prolong anything with fresh fluid. But back to the topic since the transmission wasn’t changed I highly doubt anything else has been. Could it be a fluid level issue around the electric coil inside the rear end?