Oddly enough, not included in the service manual...

What is the best procedure for removing the amp? I understand it is behind the rear seat.

 

Yes it will not be in the "engine service manual". Lexus publishes(ed) multiple volume set to cover the vehicle.

Also check out the amplifier repair shops as they may have instructions on how to remove and install the Amp.

Salim
PS: take out the carpet and the spare. You may have to detach the back seat rear liner from the truck floor.

 

To remove the amplifier in a first-generation Lexus RX300 (1999-2003), you'll first need to gain access by removing the rear seats, as the amp is located behind them, roughly in the middle between the spare tire well and the bottom seat cushion area. The process involves basic tools like flathead screwdrivers, a 10mm wrench, a 14mm socket (and possibly an impact wrench for stubborn bolts), and a socket wrench for the amp itself. Always disconnect the negative battery terminal first for safety to prevent electrical shorts. Here's the consolidated step-by-step process based on reliable sources:

Removing the Rear Seats
Clear the cargo area of any extras (mats, covers, etc.) to make the process easier.
Fold the rear seats forward and gently pry up the cargo floor cover to access the underlying area.
Locate and remove about 7 black push-in clips along the edge at the back of the seats (these hold the seat covers in place). Use two flathead screwdrivers to carefully pry them out without damaging them.

Slide the seats all the way forward: Sit in the seat, reach under past your knees, and pull up on the control bar while sliding. (This can be done standing but requires more strength.)
Flip up the back cover in the cargo area to reveal the hidden support strap, then remove the 10mm bolt securing this strap using a wrench.
Locate and remove the four primary 14mm bolts securing the seats (two at the front of the seat rails under snap-on covers, and two at the rear). To remove the front covers, spread the back "legs," tip upward, and slide toward the front of the car. Use a socket or impact wrench if the bolts are tight. Be cautious with brittle plastic covers, as they may break—use silicone adhesive to repair if needed.
Carefully lift out the seats (they're heavy, around 60 lbs for the passenger side; get help or tip/leverage them into the cargo area to avoid injury).

Accessing and Removing the Amplifier
With the seats removed, locate the amplifier (a black box mounted to the floor or bracket behind the rear seat area, near the center).
If necessary for better access, remove the spare tire cover, any foam inserts, and the spare tire itself from the well.

Gently pry loose and remove any remaining carpeted trim or liner panels in the exposed area (held by clips or screws) using a trim removal tool or flathead screwdriver to avoid damage.
Disconnect all wiring harnesses and connectors from the amp (typically 2-4 plugs for power, head unit input, and speaker outputs). Take photos of the connections for reassembly reference.
Remove the mounting bolts or nuts securing the amp (usually 4 bolts, around 10mm-14mm; use a socket wrench).
Carefully lift the amplifier out of the vehicle.
Reassemble everything in reverse order, reconnect the battery, and test the audio system.ee1243437174169f293a8390
clublexus.com


Tips and warnings: This process applies to both Pioneer and Nakamichi systems, though wiring may vary slightly. If your vehicle has a subwoofer, note it's under the front passenger seat and separate from the amp. Work in a well-lit area, and consider consulting a professional if you're uncomfortable with electrical components or if trim pieces are fragile. For visuals, search YouTube for "Lexus RX300 rear seat removal" or similar, as videos exist but transcripts may not detail the amp specifically.

 

Wow... Thanks for the info. My manual is not an "Engine Service Manual". It is a CD that covers over a thousand pages of info... but nothing on removing the amp!

The audio quality in this vehicle is lousy. It sounds like someone turned the bass and treble controls all the way up. The controls on the head end have little effect. Previous 2001 RX-300's sounded terrific but not this guy. Maybe someone put in an aftermarket amp? And to add insult to injury, the driver's door spealer doesn't work.

 

Something is wrong or as you stated an aftermarket has been installed. My feeling was that the factory Audio set up was adequate [not the very best but based on the cabin shape good]. The only issue I had was that the noise cancellation and integration with HVAC controls made the improvement very hard]. That left speakers as the only improvement option for owners.

Talking about speakers, now the vehicle is nearing 30yrs in age, the speaker cone and suspension would be shot if the vehicle was not garaged.

Keep in mind the sub-woofer amp is under front passenger seat.

Also before you invest time/effort in removing the amp, why not test it in place.

Salim