I just installed an engine block heater yesterday on my Commander. Mine doesn't make any noise when plugged in. I had it plugged in overnight to test it out. It's located on the passenger side of the motor below the manifold closer to the firewall (not the front of the jeep) You can see it from under the jeep. When you look from the top of the engine compartment the wire disappears once it goes under the manifold. That's why you can't see it anymore from above.
When you started your jeep was the coolant gauge up to temp and blowing out warm air?
2007 4.7 Liter XK | OME HD Suspension Lift | Matt's 1/2 Inch Rear Lift Spacers | Jeepin by AL HD UCA's | Rusty's Rear Adjustable Track Bar | JKS Rear Sway Bar Quick Disconnects | Black Rock Series 997 Wheels | Fred Goeske .25 inch hub/wheel Centric Spacers | 285/70R17 Goodyear Wrangler MT/R's w/Kevlar | Air Flow Snorkel | Flowmaster 50 Series SUV Muffler | Superchips Flashpaq | Mopar Skids | 4xGuard Belly Guard | American Rebel Rear Diff Cover | Powertrax No-Slip | 4.7 L Badge | 20% Tint