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 | Front OME HD Lift | Rear 4" Superlift Springs and Shocks | JBA UCA's | Rusty's Rear Adjustable Track Bar | JKS Rear Sway Bar Quick Disconnects | Black Rock Series 997 Wheels | Fred Goeske 1/4 Inch Wheel Spacers | 305/70R17 Goodyear Wrangler MT/R w/Kevlar | Airflow Snorkel | Flowmaster 50 Series SUV Muffler | Superchips Flashpaq | Mopar Skids | 4xGuard Belly Guard | American Rebel Rear Diff Cover | Rear Powertrax No-Slip | QD II Front Differential | 4.7 Liter Badge