ToolRod

Mounting downlow like Michael mounted his seems like a good option too. The type of trailer being towed might be a factor in choosing where to mount the controller. I tow a car hauler which goes from about 1,250 pounds empty to about 5,000 or 6,000 pounds depending on whether I am towing a car or my tractor on the trailer. So I do need the easy access to adjust the braking action of the trailer lest I either squeal tires or have less than adequate braking. I would prefer to have the controller down low if I were consistently towing a trailer that generally weighed the same each time I hitched up. As for where to get the ashtray, I bought mine several years back (about 2009) at the local Lexus dealer. If memory serves it was about $30. I'd try online. Now, I have a question for you guys. I would like to put the LED turn signal bulbs in the rear of the car. When I install them I get the hyper flash situation. I'd like to find a replacement flasher unit that will work with the LED bulbs. But no luck. Seems this GX flasher is a special one with more conductor pins on the connector than the standard Toyota units that are referenced at parts stores. Any ideas on where to get a flasher that is both compatable with the car and with the LED bulbs? Another option is to put resistors at the bulb locations but I prefer to not tinker with the existing wiring if I can avoid it. Thanks guys, ToolRod

Hey Michael, I'm glad the Tekonsha guys confirmed the info. With your mounting of that quality controller, I bet you will be very satisfied with the braking actions of your trailer. I do think the goal it to have a fairly "solid and stable" mount so that there is not vibration or oscillation of the controller while it is sensing the forces of the deceleration so it can generate the appropriate input to the brakes. However, I believe the decorative trim above the feet/or below the fuel and hood release is fairly solid. As long as you can see and set the controls you should be just fine. As to where the ground went... I have slept one or twice since then and therefor I cant remember. Just grab a metal brace or screw, secure the wire, and you should be just fine. Put a post in with a photo if you like. It will be great to give the next guys a few options of how to hook up a controller. Best to you.

Hey Michael, My controller is a Tekonsha P2 which allows mounting at most any angle from vertical to horizontal, along the primary travel axis of the car and not tilted sideways. The P2 controls my trailer brakes extremely well at the angle of the unit's top connected to the ashtray face as shown in the photo. I figured the P3 would be at least this good so I took a look at the Tekonsha site and called up the PDF with the installation specifications on the P3 for you. Take a look at that source and you can see the specifications call for the P3 unit to be mounted in any orientation of 0-360 degrees. Just not sideways. So I think you will be just fine mounting it at the angle that corresponds to the angle of the ashtray face. Attached to the ashtray face required no drilling in the permanent panels of the dashboard and also makes the controls very convenient to access. If you would like confirmation from a more experienced source, you may want to give e-Trailer or Tekonsha a call. But I could not be more satisfied with the operation of the P2 at the angle of the dash. One note about my installation...I tow approximately once every few months so I preferred to not leave the controller permanently in sight on my dash. That is why the "removable ashtray" option was my preferred method. If you want to make a permanent install, you may want to select a different location to minimize the wireing visibility and unit's prominent placement. But by putting it on the face of a removable second ashtray, the unit is in a very convenient location when used and completely gone when I am not towing. And it takes about a minute or two to swap the ashtrays when I need to tow or not. The spare ashtray fits either in the glove box, console, or rear right storage compartments. Good luck!!

Blackhorse, as you can see, I used a Prodigy Controller which operates excellently. I screwed the Prodigy's bracket (via the top of the bracket) to the newer ashtray with only 2 screws. The controler is in plain sight with superb access tot he buttons and knobs while being used and then when not needed I just swap back to the original ashtray and the Prodigy and modified ashtray ride in the rear side storage compartment of the GX. Good Luck

Blackhorse, yep, I bought the second ashtray at the Lexus Dealership for about $35. With the two Ashtrays, I can install the original unmodified for 99% of my driving but can swap out in about 1 minute when I need to tow my electric-brake equipped trailer. Here are the photos:

yes, the very nice MG came through. How do I upload JPG photos?

Blackhorse. No problem my friend. I have taken several photos and will try to post. Briefly here was the process. Buy a second ashtray for about $35. The gently pry the faceplate off of the tray which was fairly easy because it has plastic "keepers" that can gently be pryed loose. Then use some good screws (it is a Lexus you know) to hold your controler's mount to this new, and removed faceplate. Then snap the faceplate back on the new ashtray's main carraige assembly. Then you are essentially done. As for wiring, remove the trim panel just above your feet and find the factory prewire. On mine it was nicely taped up under the dash. I believe I used the "E-Trailer.com" adapter wire which fit perfectly. Then I routed the wire towards the console and let it peek out just to the right of the driver's seat. Then, with the assembly complete, I keep this "second ashtray" and the brake controler in the rear storage area of the car behind the storage panel. When I want to tow, I get the wire out, feed it through the controller's custom mount and plug it into my Prodigy. Then put the modified ashtray into the dash. The brake controller is in plain sight and just in front of my right hand. Also, if you need to have more convenient access to the brake controller, just tap the ashtray and the smooth Lexus operation extends it about 2 or 3 inches closer to your hand for calibration and manual operation of the controls. I have had this operational for about 5 years and it has been a great place for it to be. And if I ever sell the car all I have to do is make sure the original ashtray is installed and my wire is disconnected and I have NOT damaged my dashboard at all. By the way, I am not yet successful at putting these photos in the post. If you will tell me how to post them I'll get them up. Otherwise I hope my description will work for you. Good Luck

There are U-Tube Videos on E-Trailer that offer advice on how to properly adjust your Prodigy so that it is correctly applying the voltage to the Trailer's brakes. I notice that if I do not adjust the Prodigy braking level up correctly, the Lexus brakes carry a little too much of the load and tend to smell hot after towing. A few things I do are 1) use the owner manual recommended "4" gear selector when towing instead of "D." 2) Also make sure the prodigy is properly set per the video demonstrations. 3) It is obvious but leave plenty of room for stopping with less brake pressure. 4) I have also had my rotors turned because I did seem to glaze them after a few hard stops with the full trailer being towed. The rotors were not worn significantly nor were the brake pads. However, the rotors had a glaze due to the heat which was removed by turning a very small amount of the surface off. After the slight rotor turning, the brake feel and effectiveness returned to as new so I am very careful to go easy on the brakes as much as possible when towing.

Glad you found the plug. I also tow a electric brake trailer with my GX470. I mounted the "Prodigy" controller to a replacement (2nd) ashtray that I bought for the purpose. So when I tow, I swap out the factory ash tray with my modified ash tray with the Prodigy controller. That way, I don't have to leave the electric controller in my nice GX all the time. And I did not have to drill holes in the nice dash panels. I think the replacement ash tray cost about $30. The car tows up to the limit with no issues at all. I do leave the gear selector in "4" instead of "D" like the manual recommends. Also, I am trying to determine a good Transmission Fluid change interval since I do tow occaisionally.