A HARM works well but it requires an active radar which SAM sites turn off when the plane gets in HARM range.
So the F-15 roams around just outside HARM range while the F-35 comes in low and nails the site
Love Israel constantly whipping Syria’s head around.
HARM no longer requires an active radar. About 10 years ago it got an upgrade - it ‘remembers’ where it last saw the radar and goes over to investigate. It can either attack the last location or it can loiter in the area waiting for the SAM site to come back up even briefly, at which point it strikes. The HARM can “see” further than it can travel, so it doesn’t matter if the site goes off the air when the aircraft gets to HARM launch range, the HARM still knows where it was.
The very latest version (-E) as of 2010 actually incorporates its own radar transceiver and can attack the hostile radar even if it is shut off and has started to move. Again - the -16 can do this all by itself, no F-35 required.
Turning off your anti-aircraft radar when it detects an aircraft doesn’t sound particularly effective.
The Aircraft/HARM remembers where the signal came from, shutting it off doesn’t matter.