My service 4wd light keeps coming on in my 2000 cadillac escalade what should i do and what should it cost me??

When the 4WD light comes on you more likely have problems in the 4WD low switch circuit.well this is a dealership fix.because your 4WD is pcm controlled.when 4WD light turn on pcm detected the transfer case ratio was 0.8 - 1.2 or during condition 2 with the 4WD low switch not in 4WD low, transfer case in 4WD low,tcc commanded on, tcc slip speed from 100 to 3000 rpm, the pcm detected the transfer case ratio was 2.5 - 2.9 all conditions met for 10 seconds.see dealership has to check.many things will cause your 4WD light to turn on.dealership has to hook up diagnostic equipment to find your problem and fix it.hate to tell you.they will charge $100.00 or more to trouble shoot.then charge for labor and new part.call around and get a price check.it will be good if your vechicle has a extended warranty.