I recently noticed that the ECT swtich on the center console has stopped working or at least the little indicator light on the dash is out. My 4runner has 230k on it and is need of a tuneup so it's hard to tell from driving it whether the switch is really working or not. I pulled it out and saw that there are 4 terminals on the back, so no telling which leads to cross to test it. Is the ECT indicator supposed to light on the dash with the oil amp and other indicators when you turn the key to acc? Would that be a way of at least knowing if it is just the indicator that is out? Any one else have this problem or know how to tell for sure? Thanks!

The switch just changes shift points on the tranny.
Set it for POWER and take off, watch the tach to see at what RPMs it shifts from 1st to 2nd, 2nd to 3rd, etc.
Then do the same (accelerate at the same rate as before) in the ECONO mode. The shift points should be different, and you know it's working.

I had this same issue at one time happen to me. When I took into the shop, the way it was explained to me was that the Indicator acts like a fuse. If the light is not on, then the ECT is not working, cause the system dosent know that the button is pushed in. Hope this helps.

Thanks for the info. It was hard to tell on the shift points even when the ect apparently did work. I can get a switch cheap enough off ebay so I'll just try replacing it first. I'll try replacing the dash indicator bulb second, and if that doesn't work then I'll have to dig in deeper.