Tried to put the truck in 4wd today, light on the dash doesn't come on. I have an 02 2500 4x4, is the 4wd engaged by vacume? I couldn't tell if the truck went into 4wd, tried 4 low, it felt like it worked but......

 

If you are not getting a light, it could be two problems: Either the bulb is burned out (or a bad LED), or the truck really isn't entering 4wd. You should be able to tell if the truck is in 4wd when you drive... If you switch to 4wd and drive on pavement, you should feel it shuddering. You're not supposed to do that because it will eventually damage your truck, but trying it once to see if it's engaging is ok. If you're not feeling that, then it's a problem with the 4wd system and the lack of a light is correct. I am not sure how the 02's worked for 4wd... I thought the 02 2500s were still considered 2nd generation (you do have the "first" redesign look to your truck, don't you?), so you might want to ask around that forum.

 

The light on mine is out too, but I can tell the 4WD is still working. Gonna have it looked at next service. Anyone know if it's an easy fix to replace the light?

 

Mine had the same problem, the intermediate half shaft vacuum was shot. The front axle is always connected but the transfer case hasn't engaged the axle until you pull it into 4+4 and it works great, instant shift. The part of the vac that runs the 4+4 light is ca-put . Replace the vacuum unit and the light should work again. I replaced mine with a cable, so I could run 4+4 lo with out the front axle engaged, for extra low pulling in 2 wheel drive. In the winter , when we have snow covered roads, I keep the front axle engaged with the cable but keep the transfer case in 2hi until I need 4+4 , then its a quick pull and instant engage. No waiting for the vacuum to hook up the intermediate shaft.