Manual nav hack switch

[dreyfus]

Here are the steps for installing a manual cutoff switch for temporarily disabling the speed signal going to the head unit on your ES350.

I believe drivers should be able to choose whether or not they can safely operate the features that Lexus automatically disables when moving (dialing phone numbers, viewing MP3 filenames, etc.). The Lexus nanny lockouts are too restrictive and responsible drivers are quite capable of safely operating these features. Having said that, ANY distraction while driving is potentially a deadly one, so let the user beware! Be safe. Don’t even think of viewing DVDs while driving.

The nav map without the input of the speed signal doesn’t move smoothly because the car is relying on GPS information only. The car locator may also be inexact (but close) in its positioning. Turning the speed signal back on restores normal operation. You can switch back and forth between normal operation (speed lockouts on) and cutoff active (speed lockouts off) without interrupting any nav functions, such as route guidance. However, I recommend using only normal operation when near route guidance instruction points (i.e. turns) to avoid any chance of error.

You can use any SPST (single pole, single throw) switch - rocker, toggle, or button. If you want your switch to be illuminated to indicate whether or not the cutoff is active you’ll need a DPDT (double pole, double throw) switch. Don’t run the current for the LED on the same circuit as the speed sensor.

I used an illuminated rocker switch from DigiKey (part # 67-1933-ND) because it matched the nearby switches and I wanted an LED indicator. This switch is SPST, but I modified it to function as an inverted DPST switch. This was a lot of work and I do not recommend you do this. Just buy a DPST switch and save yourself the effort.

First, follow the steps for accessing the back of your nav unit (found elsewhere in the forums). http://clublexus.com/forums/showthread.php?t=234398

I used insulated blade connectors to make all my connections. You will need an inexpensive crimping tool to attach them to your wires. They are quick and easy and allow the original wiring setup to be restored quickly.