When I put it in 4x4 it doesn't light up on the dash indicating it's in 4x4 mode. Would this be a bulb problem or a wiring problem? Any ideas?

 

are you SURE thats its going into 4x4? when you put it in 4x4 its takes few secs to click in, your light on the dash wont come on untill its actually in 4x4. so your problem might be that its not going into 4x4....

 

We have over 3' of snow here so it's not to hard to tell when it's in 4x4.

 

then it could possibly be your light might be out (its rare but happens) not sure how how easy it would be to check/replace it since ive never had to do it.

 

toofancy83 is right, it could be a burnt out light however is not very common. I've had a defective IWE solenoid before where the mechanical portion of the solenoid worked (which meant my 4x4 worked) but the electial portion witch triggers the light was malfunctioning.
If you've never had to change yours before, this might be a good place to start considereing how common they are.

 

if your 4x4 is working, i would start with what jun_ior50 said. the light being burnt out is VERY uncommon, i have never personally seen a acc dash light ever burn out.