selector light flashing on 4 wheel drive

[outdoor7or24]

So on my 2020 1500 when I shift from 2wd to 4wd high/4wd auto / 4wd low, the light on the selector is flashing and not constantly lit.

Today it said something about service traction control, but it went away quickly. The error warning did not show up when I restarted a few minutes later.

I noticed the flashing light on the selector a few weeks ago, but it seems like it still shifts from 2wd to 4wd.

Any thoughts?

 

[Pikeman_66]

back in the GM world that symptom usually means you have 1 of 2 things wrong or both. the switch is shorting out or there is a bad actuator in the front-end locking mechanism or the transfer case. not sure if that applies to Ram but all the 4wd drive systems are pretty similar.

 

[outdoor7or24]

Is this something I can diagnose myself or a trip to the dealer?

 

[Pikeman_66]

There is a way to do it yourself if your handy with a multi meter to check the possible faults, I found over the years it’s much easier and faster to have the dealer hook it up to the machine. We had a whole fleet of GM pickups at work and this was fairly common occurrence. Like i said that’s GM experiences I have had. Other makes work similarly but the way they wire architecture is I have no clue. None of those items were a major repair item and they usually had us in and out in half a day or less as long as they had parts on hand. I would just take it in if it were me and save crawling around.

 

[outdoor7or24]

Looks like this was done here, but just pull the part and replace.

Service Traction control, trailer brake, and 4WD...

This is cross posted on another forum as well, but I went to start my truck today and out of nowhere I got all three of these messages popping up at once. Everything runs and drives fine so I am scratching my head. Just a glitch perhaps, I am going to unhook the battery tomorrow and let it sit...

5thgenrams.com

Here's some more detail on this thread... issue seems to be oil leaking on the wire harness, which btw could be mine as the oil filter was loose from recent oil change and dripping in this area described below. I will check this out.

2019 Ram 1500 (3 Errors - Service 4WD, Service ESC, Service Trailer Brakes)

Just had these three pop up while driving on the freeway. Truck has the Maximum Care Extended Warranty (Just hit 60k miles). Anyone every have all 3 of these pop up at once? Its going to the dealer once I call them on Monday. As luck has it, this happened after 5pm on a Saturday.

5thgenrams.com

Also in this thread as well the 4wd actuator.

https://5thgenrams.com/community/threads/service-4wd-system-notification.33968/

Hopefully this post will help others in the future.
Now just to determine if a test can be done on it at the house versus a trip to the dealer....

Part is 68399418AA
per @wrxified :
The dealer will likely do some basic troubleshooting. One thing I saw as a note on the work order is they measure resistance on circuit G303 between the DTCM and actuator. It should read 3.0 ohms. Mine was reading .4 ohms so they knew it was bad. I don’t know the details on how or where to measure that circuit but if you are technically inclined maybe you could do this. That or just replace the actuator and be done with it. It’s been the reason for these 3 codes on nearly every persons truck that I’ve seen.

 

[outdoor7or24]

So I am looking up parts online for Part 68399418AA

On Amazon this guy writes a review on a Dorman brand for his 2019 truck and it was positive, maybe I can save $250 on the part...
Alfredo Suarez Alonso
5.0 out of 5 stars So far so good, Ram 1500 2019 5 gen.
Reviewed in the United States on December 6, 2023
Ram 1500 2019 laramie sport 4x4 hemi 5.7, a few months ago the check engine come up with other guys, service 4WD, service electronic stability control and these codes were displayed, U0418, U1440 , U0403-00, U0415-00 and U1003-00. but the strange thing about all this is that when I put the truck in 4x4 auto or high and drove it like that for a while all the lights went out, I checked all the harnesses and wiring and everything was normal, so the first thing I changed was the ABS module and nothing, so I took it to the dealer for a diagnosis and they told me that it was the transfer case motor that was out of range if not the Transfer case module I changed the motor and the position sensor and guess what, again everything stayed the same. After a lot of research I decided check the 4x4 actuator.. and that was the problem, the actuator was stuck in out position, so only when I put in 4x4 all modules see it in the right position. A real headache, and the dealers guys with all they specialized tools can't notice that. So i change the actuator and now is all back to normal..

i hope this can help someone else...

https://www.amazon.com/Dorman-600-399-Wheel-Differential-Actuator/dp/B01D8VMBYU/ref=sr_1_2?crid=1XIEAASBA27X5&dib=eyJ2IjoiMSJ9.i7rZIiE3UiCjysHqyVKEZLIRizrFWVZniirJLQRXXkSDSZMpn0iSUj5OZwwjKy5rvGlGyymzSp850uxik6y7ndzlJwccik8Ti2H0UE5WWJNT37JPLmsC734v4So451_rIB_zgJlc_3jfzD1qVinQT7mkRXvghmK-YC30KWVjqEQzuJ2CXi8HCphD-DPpkmUmVinvlAYk5BFaEvAITp4VXlhd0F3RA-4NK0-Cm0tO8PwEfAgp7W5sc0fHwM65d4vdrjKynIM-edms0OJ8eFsPSkkWso7rNVB6CZ9lS5QjYu8.75sLqVwvAXy7uJW_Rlr0tjyfdzy4UQ82iRpN1n7YaZQ&dib_tag=se&keywords=Mopar+68399418AA&qid=1715124379&s=automotive&sprefix=mopar+68399418aa%2Cautomotive%2C104&sr=1-2