MY LEXUS ES330 2004 MODEL IS MAKING A CLICKING NOISE BEHIND THE CONTROL PANEL AND BEHIND THE PASSENGER SIDE DASH. IT STARTED OUT SPORADICALLY BUT NOW IT'S A CONSTANT CLICKING SOUND. HELP!

It doesn't sound like it's the turn signal flasher, sounds as it is the recirculate door actuator. Does it sound like it's coming from the passenger side, behind the dash. They will click when the ignition is first turned on and as you stated, at random times.

What type of vehicle?

It is located under the right side off the dash. Remove the plastic kick panel and you will see it. The screws to remove the panel are just under the glove box. Once the panel is removed you will see the motor housing it has an electric plug with three wires.

You have a wiring problem on the control side wire . One wire will have B+ voltage the other goes to the PCM- engine computer . The engine computer suppy's a ground when triggered by cam sensor . Your problem is you have a bare wire touching ground making the injector fire all the time the key is on ! Check the wiring harness from the injector to the PCM for rubbed through spots !
The PCM must be inside the passenger compartment under the right side dash or behind the right kick panel . Here is a web site for free wiring diagrams . http://www.bbbind.com/free_tsb.html Enter vehicle info. year , make , model and engine size . Under system click on engine ,then under subsystem click on fuel controls . Click on the search button , then the second blue link. Second diagram down is fuel injector electrical circuit. Dark green wire is the controlled ground . That is the wire to check .

Engine Control Computer is located in the front seating area, passenger side, under dash, mounted behind kick panel

The ticking/buzzing noise is a common problem on the RX330. There is a plastic pin that is attached to the instument panel which inserts into a plastic housing on the firewall. This holds it in place to the firewall. It is a design problem that model year. In the 2006-models on have a piece of felt covering the plastic pin to reduce the vibration noise. The same noise can occur on the passenger side behind the glove box. You can try to access the white pin and stuff some felt/cloth, but it is difficult with out dissassembling the dash or glovebox.

the polos have a recycle flap motor located on the passenger side behind the glove compartment and a temp. flap motor also located behind the glove box but more towards the center of the dash and near the bottom.one or both of these motors are probably stuck or slipping on the plastic gears.

there are fuse blocks under the hood, under the driver side of the dash and under the passenger side also. the ones under the dash may be located behind the kick panels.

the reset switch is usally located either in the trunk on one of the side panels or on the passenger side under the dash on the kick panel

I had a similar annoying noise with the root cause being found in the air-mix servo. This servo motor box is one of three I believe and is located on the passenger side of the climate control system and accessed by removing the glove compartment (4 screws) and the panel down just above the floor. The servo in question is located behind a couple of heater tubes and you need a stubby phillips screwdriver to remove it. Disconnect the wiring plug. The servo has a damper actuator on one side. Hold with the actuator down and pry open the case. Don't fret if the snaps break because the unit is held together with screws anyway. Clean the contacts inside the box and re-lube the gears and contact plate with silicone grease. Reassemble and reinstall (kind of a pain). Works fine now in my auto (all is quiet again!) and saves hundreds of bucks vs. a visit to Lexus service. Shield the servo from heater tube heat with some aluminum reflective duct sealing tape. I think the heat breaks the lube down and caused the servo voltage to become errant, causing the servo to "hunt" and generate annoying noise. Good Luck.