I bought this truck several months ago. Been wheeling a few times. The little green light on the dash had never come on when I shift into 4wd. Within the last couple of weeks, it randomly comes on while driving around town in 2wd. Sometimes for a few seconds, but it usually just flickers. No biggy, just annoying. Anybody know why this happens, and how I can fix it? Thanks!

 

I would get to checking the ADD vacuum hoses. You probably have some vac leaks.

 

the light isn't a dummy light. it is triggered by the vacuum valve moving in the system, when the valve moves far enough then it hit the switch and turns on the light. You may have a problem with getting into 4wd. When you put it in do you know if it has actually ingaged? Trace for vacuum leaks - this is where most of the problems are.

 

Shucks, you snuck in while I was typing - or trying to

 

Thanks, I'll check for leaks. Where should I start? Still learning.
Weird part is, when I put it in 4, it is in 4, no doubt about it. A month ago, I went to Brown's Camp. Not to far from where I live. I got up to my nerf bars in mud and got out. I was plowing mud for a while with my IFS. (I have to buy a power washer. Usually costs around $8 at the drive in). Point is, I know the front was spinning. Even stuck my head out the window to check. Of course my tires were pointed left. Put some mud in my buddy's face when I asked him to check his side as a bonus. The light never came on. It has not flickered for a day or two, but when it does, I am in 2wd just drivin' down the road.

 

I just posted a thread on this...

However, with me the light flickers when actually in 4WD, and only briefly suggesting a very small leak. I don't think its actually NOT in 4wd for the brief time it flickers though. It was mentioned that the valve has to go "far enough" to hit a switch. Is it possible that not far enough still can mean you are in 4WD?
Also, I found the vacuum hoses... replacing them seems rather simple. I'll do that for S&G's at the very least.
http://www.off-road.com/toyota/tech/add/

I'm thinking that the tubes got messed up from battery acid from a leaking battery a few months back. Additionally I think this same battery acid hit the AC freon hoses too. It's been out since about the same time. However, AC is the last thing I need right now so its on the back burnner.

 

BTW, I have manual hubs.