ECT Power Button

[AvalonTruck]

Hey all! Could use some help. I have a 99' Avalon, and am having issues with the ECT power switch. It started a year ago, where it wouldn't turn on when I pushed the button. I happened to leave it engaged and at some point it came back on, so i left it on until i no longer needed it. (The extra power is helpful for towing.) After that, it seemed to only want to engage after about 30 minutes of driving. I was OK with that, but now I am back to it not turning on again... it's not respecting the normal warmup arrangement that we'd developed. Thoughts or suggestions?

[jdmccright]

Two possibilities I can think of:

1) The button itself is not working correctly. Either the contacts inside have become oxidized or the wires have broken or a bad ground. As the weather gets colder, things shrink and connections may lose contact internally.

2) The issue is seasonal. You stated it started about a year ago, as it is getting colder. The transmission takes longer to warm up in the winter, so it will not shift normally until the minimum coolant temp has been reached.

The button really just changes the shift points higher in the RPMs where the engine is making more power.

There may be more, but that's what I got so far for you to start with.
Hope this helps!

[AvalonTruck]

Both of those sound reasonable enough. I'm not looking forward to taking the center console trim off again (grumble grumble), as i fear someday i'll over-torque it and break it. However, it is a good start, and it's by far a better first step than an expensive tranny repair. You could be completely correct in the seasonal issue. If I remember correct, and I probably don't, i think it stopped working last winter and started the warmup scenario in spring. i suppose while i'm at it i'll check the tranny fluid level too. Was a little sluggish the first time I put it in drive after a good 4 day holiday sit. Yeah, ECT does come in real handy going up steep hills with a lawn tractor or two on a trailer, or a load of lumber. I do use it occasionally to get extra power from the "starting gate" of rush hour too. heh heh. I'll report back if I find a cure for the ailment. Thanks for the advise, I appreciate it!

[AvalonTruck]

Well, i went to the junkyard and found a matching switch. Installed it, and same results. I changed routes to work, and found that a really hard bump in the road caused the ECT to engage for a while... long story short, i found the problem. It was the bulb in the dash. I swapped it temporarily with the light and socket intended for the cruise control indicator, and it worked flawless, so i smashed the bad bulb with pliers and pulled it out by it's internal wires... you pretty much have to do it that way because of the design of the twist-in socket. The local parts store tried to match it but apparently they don't carry the recommended minibulb, but the bulb aisle yielded a close enough fit, and the new bulb is in and working fine. Thanks!