4wd issues 2008 1500 Silverado

[Taylork92]

Recently my 4wd has been having issues. It was working fine until about a week ago. Turn the nob to engage the 4wd and it says it's engaged, however the driveshaft wasn't locking and I was still only getting power tinny back wheels. I tried to start with the most simple thing I could think of and put in a new 4wd actuator. After installation of the new actuator the drive shaft seemed to be locked and I thought I was in the clear and had my 4wd back up and running. Now, it seems like the drive shaft is only engaging every once in a while. Could it possibly be a bad 4wd switch? Where would you focus your attention now that you have all of this info?

[Taylork92]

There is also no warning or service 4wd light coming on