This happens to me usually after I go through a car wash. I start up the car and the red light comes on the transfer case switch. There are no error messages on the dash. I even plugged in my OBD computer and it didn't show anything wrong. When I press the default 4HI switch the red light will blink for a while and switch to the regular 4HI mode. Could this be caused by a bad ground ? If I drive around with the red light on the car gets about 6 mpg (default setup) and goes to much higher revs before it changes gears.

 

I know this may be hard to track down. I'm even thinking about changing the transfer case motor. I just wanted to know what is the easiest way to tell if the car goes from 4Hi to 4Hi lock, what are the differences I can notice straight on. Maybe the switches are showing 4Hi when the car is still in 4Hi lock. This year has been nothing but trouble with my H2 FML.

 

i bought mine used. the light seems to randomly stay red and i get the service 4wd warning. sometimes it goes away as soon as i restart the vehicle other times it stays for days at a time.

took it to the dealer and they hooked up their portable transmission computer but could not figure out what was causing the problem. it doesnt appear to affect the driveability but ive never checked the gas milage during one of these episodes. ill have to look into that next time.

if anyone else has any thoughts on the matter id love to hear them.

 

I replaced the sync motor for around $160 and fixed a similar prob. 3 bolts hold it on, plus 1 for the plug pigtail. Plug is the hardest part of the job, has a special GM locking tab that has to come out first.