Valves not workin

Okay so i had my truck parked without usage for about a month and i start airing up my tank and try to raise my truck and the rear right bag dont want to air up. The valves do not click or anything, i checked the ground and the switch and seems to be good. I replaced one valve to see if that was it and nothing? Any ideas as to what can be wrong?

make sure its gettin power when u hit the switch...if the switch is workin and the ground is good and uve changed the valve then u have to have a break in the wire somewhere....get someone to hit the switch while u put a test light on the valve....

Ok ill try that out, Thanx.