This mod was inspired by rook who did the research in another thread here:
http://www.toyota-4runner.org/showth...threadid=38010

I get the blinking TPMS dash light (LED) when I run winter steel wheels without sensors. This switch is a cheap alternative (less than 5 Canadian bucks) that will defeat the light. You can also use it if you run other wheels without the TPMS's or if you get a system fault that is big $$$ to fix.

The default electrical principal behind the system is that it fails safe. The default condition is that the LED is lit using a ground path in the gauge cluster. The ECU closes a circuit and creates a ground path to bypass the LED when the ignition is on and everything is OK with the system. The ECU opens this circuit to turn the light on (fully open when it senses low tire pressure creates a steady light on; cycling open/closed when it senses a system fault creates a blinking light.) Merely unpluging the ECU to bypass the system disables the ECU but actually creates a steady on LED.

This switch installation provides another path to ground to bypass the ECU ground. It is easy to get to the location behind the lower panel under the glove box.

The research shows that this principal probably changed in '07 and later so this mod may not apply to later 4th Gen's.

Here is the stock wiring diagram for the '04:

Attached Images

320 061tpws.pdf (31.8 KB, 6309 views)