4hi light not staying on upon startup, can shut off and try again a few times and it will stay on, when off I get service 4wd warning , 2003 h2

 

Search the forum here. There have been many a post regarding this switch. On My 2009 H2 Lux it was a Bad Switch that caused service the 4 wheel drive. Also I have heard of some who have removed the switch and took it apart (Not Easy..Soldering required) and shot some Caig Deoxit inside to clean the contacts. I'm not saying you should do that but there could also be other issues that are covered in the older posts.

Good Lick on your hunt,

 

I cant get search function to do anything , it comes up with anything but what I search, locked it in 4hi then back to regular 4hi a couple times, works like normal again...for now

 

Ok I searched "Service 4 wheel drive".. There is one long post but look at all the other posts there may be more on this page.This thread talks about the H3 I think but might be relevant to your problem.

https://www.hummerforums.com/forum/h...ht-dash-34726/

 

Cool thankyou, looks like what i did but only did it 3 or 4 times, ill see if it continues to be fixed over next few days

 

Glad you working at it.. Also they like it here especially "Doc Olds ..Supper Mod " when you start a new thread like you have done and not post on the older threads.
Maybe some of the other guys will jump in here with some other suggestions. We got some super smart HUMMER guys here. It may takes a while before you see some replies here as some are off and on this board.

 

Interesting timing on that post. This morning I had a Service 4wd message come up. Then it would just turn off on its own. The indicator light on the switch was lit up. But I did notice the back lighting in the driver door control module switches would dim when I put it in park. Even flicker. I replaced the original driver door master module last year with an aftermarket one, the white paint on mine was faded. However I found it and swapped it back in. Just finished literally 5 minutes ago. Problem solved.

I would start with a switch in the dash, it's pretty common and easily replaced. Then the electric motor on the back end of the transfer case. Pretty common failure, but only a 10 minute swap out. But.... If your lights are flickering on the driver door control module when you go in and out of park.... The module is bad in the door.

 

This is the cheap aftermarket one I tried from Amazon. It did last one year....

 

see if you can find someone with a tech ii or get one yourself(its worth it) and it'll tell you exactly what's wrong when you read the tccm.