4x4 doesn't work on 2003 Suzuki Grand Vitara

After all this rain we have been having here in QLD, our road was wet and I put my car in 4x4 to find it doesn't engage, how can I fix this with out to much cost?

Asked by for the 2003 Suzuki Grand Vitara
Get it diagnosed by a 4WD shop or a Suzuki specialist. Cheapest way if you can't diagnose it yourself is to get it diagnosed by an expert.
If you want to find a specialist, here's a directory link for you: