Service 4wd light when wet.

[Redfisher1974]

Hello, I own a 2017 outdoorsman with a 3.6 that has had a issue for a year or more of service 4wd light coming on when wet. Think i may have fixed it (knock on wood) so thought id post it in case it may help others. As i researched this problem a lot without a lot of answers.
(Back story).
It started with light only coming on when going through car wash with under carriage wash, light would come on but go out after a few miles..
Then at later dates it started to happen in heavy rain, then recently it would happen just siting out in the rain.
After putting it off for some time I decided to try and figure it out. I took garden hose and started at the transfer case. Gave it a good soak with water at all connections and wires etc. then started truck, did this at all main connections.. when i got up to passenger side fire wall under hood I sprayed the black/grey junction box connector mount on inner fender and boom service 4wd light goes on. Awesome i found problem! Took it apart dried it out and filled with dielectric grease. Been out in rain storm no issues and car wash no more issues..
Maybe only a temp fix but at least i know where issue is and can fix properly if needed later.
I can add pics later if that would help.
One thing I noticed is the block is right under the space between hood and fender and was kinda angled upwards so i figure when raining water was dripping down onto block and seeping in making a short maybe?
Also when light was on and you accelerated the light would go out under the g force but if you hit the brakes it would come back on with the negative g force? I wonder if the movement was making the water move around in the junction block? I dunno was really interesting.. lol

Anyways hope this helps someone with this annoying problem. Cheers my friends!

 

[jasonLmarsh]

I have the same problem with my 2021. After driving through deep water, and a day or two after every oil change, I have the same issue. Mine is corrected by unplugging the plug on the front axle (right below the oil filter...) and cleaning it out, drying it off and reconnecting. The lights go away and don't come back until the next big rain, or oil change.

 

[Redfisher1974]

Funny you bring this up! A week after my post above yours my serv 4wd light started coming back on, but not when wet. It would come on after starting truck and backing out driveway every day. Would shut off after a block or two. So i worked on all connections from front axle up beside the rad and back to firewall.. lights been gone since.. i also went to back no maintenance road and spent 20 minutes running truck through 4 high n low many times to exercise it.

We’ll see how long it lasts this time, lol

 

[TunaFish]

If you still have pictures of the junction box on the fender well, I’d love to see them. I have this exact problem. Replaced the actuator and put dielectric grease in the connection but the code is back and won’t shift into 4wd until it clears. I’m in a 2015 1500 Bighorn Ecodiesel.

 

[jasonLmarsh]

If you still have pictures of the junction box on the fender well, I’d love to see them. I have this exact problem. Replaced the actuator and put dielectric grease in the connection but the code is back and won’t shift into 4wd until it clears. I’m in a 2015 1500 Bighorn Ecodiesel.

Here's an update on mine that might surprise you. I finally got it fixed permanently. The problem was that the truck wanted a MOPAR BRAND actuator! I was so pissed, after spending money on 2 different actuators on amazon (Dorman and chinese), both didn't work. I sent the truck to the Ram dealer for 3 weeks and they tried everything they could and kept saying they think it's the actuator and I kept refusing that because I "already tried 2 new ones, so it can't be that". I finally gave in and got a Mopar brand actuator and instantly all my problems were gone. So if your new actuator didn't come in a Mopar box, you might give that a try. PS, dealer wanted $600ish but couldn't get one due to backorders, I got mine on ebay, from a dealer for around $285 I believe.