4wd indicator light
 

My 4wd indicator light on the dash would only come on intermittently when shifting into 4wd. But the 4runner did go into 4wd mode every time. The repair shop says its a bad transfer case ecu, and the total repair bill will be $1200. I'm already several hundred dollars into this repair for diagnostic costs. Does this sound like a legit repair?

SR5? TRd?

It's an SR5

Run. Highly doubt that diagnosis for an indicator light light.

Make sure that your 4 wheel drive is fully engaged. When operating the manual transfer case shifter (or 4wd selector switch) on a dirt road (not on pavement) move your steering wheel right and left while rolling to make it easier for the 4 wheel drive to engage. You can put it in 4 wheel drive and still have the rear axle moving the vehicle and the front axle not be engaged, thus the 4wd indicator light not being on.

It doesn't always engage properly, especially if you don't use the 4 wheel drive regularly. If this isn't what your problem is, hopefully someone else will chime in with help.

how have you verified this? it is strange the light won't come on but your rig will be in 4x4 every time

try going into 4x4 from neutral rather than drive. see if that helps at all. sometimes with the part time 4x4 you may have to go from drive to reverse and move a bit for it to engage. try it from neutral first, then shift into D

Are you referring to shifting into 4H or 4L?

You can shift on the fly into 4H. Different process for 4L. You may need to drive forward a bit or move your steering wheel to fully engage. May not engage at a complete stop.

I know the indicator light will flash on and off if 4x4 is not fully engaged. It will be a solid light if 4x4 is fully engaged.

I've noticed that your shifter (dial) can be turned to the 4H/4L position but still not be fully engaged. One time I thought I was in 4L going up a snow covered hill but realized I was not fully engaged as the light was blinking - even though the dial was turned into the 4L position. Sometimes you may need to drive forward a bit just to fully engage.

I have a 2015 SR5.

When the light isn't coming on, I can shift into 4wd high, put it in drive, go forward a bit, put in reverse and go back a bit, and the light still doesnt come on. I can goose the gas and see the front wheel spin if I'm on dirt and verify its in 4wd. I can do the same for 4wd low, and the gearing changes, but no 4wd light there either.

My understanding is that the 4wd light should come in blinking if 4wd has been enabled, and then go to solid when engaged. 4wd is engaged and the light is neither blinking nor solid on.

This problem is intermittent though. Sometimes the light comes on just fine. That's what has me sort of perplexed. If an ECU goes bad, I would expect it to fail all the time.

I'm just glad it was failing when I took it into the shop. "No problem found" would have been totally annoying.

Just an FYI;

2011 4WD light constantly flashing/blinking | Toyota 4Runner Forum [4Runners.com]

Perhaps the repair manual will help you: TOYOTA 2016-2019 4Runner Repair Manual RM27F0U

Page 1347 has the wiring diagram for the 4WD system.

Page 2886 is test of the 4WD indicator switch.

Page 2898 has diagnostic steps if 4WD indicator does not come on.

After looking at many pages in this massive manual, my guess would be the 4WD indicator switch may be the problem. Easy to test and replace, and a lot less expensive than replacing the ECU.

The correct name is the Transfer Indicator Switch. There appears to be two of them.