Locking diff light flashes in 2WD

Need some thoughts,, my locking diff light flashes continuously while in 2WD. A clue would be it seems to happen more on rainy/snowy days or after car washes. I`m thinking electrical but dont see anything obvious at the actuator. Has anyone else had this problem?

 

Might be electrical as you mentioned as it happens during rainy.snowy days . There might be a short somewhere

 

Does it still work the locker when pressed?

 

First you say it flashes continuously, then you say it happens more in rain, etc...

Go back and describe more when it flashes, when it doesn't. Does it flash for the entire trip, not the entire trip? When will it start, when will it stop.
Try to be specific and give examples, with 'always', 'usually', 'sometimes', 'occasionally'.
The more antecdotal evidence, the better....

Next, any evidence the rear is actually locked? No chirping tires, no resistance to turning?
Unless you are absolutely 100% without a doubt positive that it is NOT locked, next time it is flashing I would jack up the rear axle and make sure its not locked (free to differential).

Have you regeared? This is a known issue on people who have had the rear diff apart and was reassembled and damaged the lock position feedback.

After all that, the next step in testing is, the next time it is flashing, (without shutting off engine or anything), climb under the truck and disconnect the rear lock feedback switch. (NOT THE LOCKER COIL). This should stop the light if the issue is in the lock feedback switch.

This is T13 on the schematic located directly on the rear diff.
NOTE, there are (2) connectors going into the rear diff pumpkin.
The feedback switch is black connector (rather than grey) on my truck with a black wire and a blue wire
(WRONG WIRES, lock coil are Gray connector with red and white wires.)




If the rear is not locked, and disconnecting the feedback switch stops the indication, 99% sure the issue is in the switch, or plate in the diff actuating the switch.
(double check by measuring resistance across that switch with an ohm meter).

NOTE, DO NOT REMOVE THAT SWITCH. Reinstalling a replacement correctly requires removing the 3rd member, or possibly some funky work-arounds. Read and understand some of these threads before proceeding.

E locker stuck in locked position after gear swap | Tacoma World
https://www.tacomaworld.com/posts/24459836
Help Needed - R Diff Lock Indicator Switch | Tacoma World


This STOLEN picture shows why if you remove the switch (with plunger), its difficult to get it back where it belongs

 

Picture stolen from @perpetualenigma3
What is this going into the rear differential? | Tacoma World




And let me reiterate again, dont remove that sensor from the diff, just discussing removing the ELECTRICAL CONNECTOR from it.

 

Thank you for responding,, Yes I am positive that it`s not locked, no chirping while turning, tested it out in my back field, it locks and unlocks normal while in 4Lo. anytime this truck is wet the light will start flashing at start up and continue to flash for the entire 18 miles to work or back. NY state will fail this truck at inspection if any warning lights are illuminated and my inspection is coming up. I`m curious how a system that only operates in four low is getting power to flash the light while in 2 wheel drive. I dread the thought of having to take it to a dealer to be looked at.

 

mine flashes when trying to engage in 2wd, it only works in 4L

 

If you can strongly connect the symptoms to moisture, there is an extremely high chance this is a wiring issue. If that wire or its connectors under the truck short to ground, the light will turn on.

What you need to understand is that the rear diff lock has 2 separate electrical circuits. The first is a magnetic coil that locks the diff. This is only active in 4lo when you hit the switch. The second circuit monitors the diff status (lock vs unlocked). This operates all the time the truck is on. It does this because a mechanical fault that locks the rear diff or prevents it unlocking correctly could cause a steering issue due to higher steering forces and tendency of truck to not turn.

Somebody is going to have to track down where that wire or its connectors and switch has a short to ground and fix it. That or depin that wire off at the ecu or a connector and live with a locker dash display that never works when you engage the locker.
It may be incredibly hard to track down the issue, or super easy and somebody on a creaper will find it in 30 seconds. Cant predict which.

It could also be in the ecu or display cluster, but chances of that are very negligible from anecdotal evidence.

I recommend using a hose to see if you can manually create the fault.

If you can figure out how to manually create this condition, any semi competent mechanic can track it down pretty quick. And if they can identify the section of wire where its occurring, they can also just bypass that piece of wire all together.

If you take it to somebody, give them this entire schematic with the connector pictures and tell them that you believe its a bad wire or connection in the 'Rear Diff Transfer Indicator Switch' circuit, or its associated connectors. But tell them to NOT remove the position switch from the rear diff without your express permission. (That switch cannot be reinstalled by any normal methods if removed, therefore it is NOT to be removed without careful consideration.)

 

@BigWhiteTRD Great posts! I learn so much reading your posts. Really appreciate you sharing your knowledge!

 

Thank you again to all that responded, I learned a lot,, it was a great idea to try and recreate the scenario with the garden hose, I just need to find a place to do it, it`s 10 degrees outside. Thanks again.

 

Quality Post of the Day award goes to Big White TRD!

 

How about a wand car wash?

Sorry, I don't understand this 10degrees you mentioned.