Front diff 4WD activation

98 Chevy K1500 213K
At times my front diff will try to engage while driving? It is pretty loud too, I replaced the 4WD actuator on Tue and today it engaged again, I took out the actuator and it was engaged, so I plugged it back in and started it, it went back to normal so I left it unplugged...any suggestions???

It sounds like a short somewhere. I would start with the switch on the dash. If you can, unplug it and check the connection on the accuator with a test light to see if gets power when the switch is off. It won't cost you anything to test it. It would be helpful if you could get a buddy to crawl under the truck and watch the light while you play with the switch.
Good luck. Let us know how you make out.

Figured it out! Troubleshot it down to the transfer case switch, was shorted out internally. $30 at the dealer. Thanks for your help!