Okay so my passenger side floorboard got flooded (sun roof drain failure combined with high pressure auto car wash) and now after going a couple miles I get numerous error codes (transmission fault, hdc, amber brake light)and the suspension lowers. I did go ahead and check the battery and installed a new brake light switch just to eliminate them so seems pretty certain it’s related to the water. My question is….what now? Is the wiring damage a user friendly fix or is it time to take to dealer? Thanks for any advice.

 

Depends on where they water went. The floor board can get soaked three ways, not just the drains. Check your HVAC filter, its its wet then it is getting into the cowl and then into the cabin air intake. The exterior a-pillar trim can also leak. The issue is if it gets onto the central junction box (CJB) which is the brain of the truck and not replaceable. If it dries out, you might be fine. But constant water will cause corrosion issues. The only wiring that usually goes bad from water is remote related, the remote stops working. If you go to the dealer, you may as well get a different truck. They will cost you a lot of $$.

 

My 06 had a a similar issue and I recall there was a splice/crimp in the brake switch line in the main wiring loom located right under the front passenger door sill. If you pop up the front passenger door sill and also the trim between the front and rear passenger seats by the floor, it's pretty easy to pull up the carpet and find this loom. It's bound up with electrical tape that you need to unwind and replace. I found a crimped wire in there that was only wrapped in electrical tape and badly corroded by water ingress. I can't believe LR would do such a shoddy splice, but I read on other posts and found it on my rig too. There was extra wire in the loom so I cut both ends back until I had clean copper, soldered, plus heat shrink so it is now water tight. This didn't fix my issue, unfortunately. But it's worth checking out if you had a lot of water in the passenger foot well. The wire loom runs down a channel in the body that stays wet long after the carpets have dried.

If it's worth anything, my issue was fixed with a transmission control module. I left the cover off the battery during a hard rain and water got in between the windshield and the cowl. Water in the battery compartment drips down to the TCM which is directly underneath.