I recall reading someone having problems because their electrical got wet when they went through a car wash and the underbody spray nozzles somehow wet their electrical components causing problems. I'm wondering if this truly is possible as i have never encountered this myself. I'm am concerned about this because now that spring is on the horizon I would like to give my underbody a full wash to get rid of salt, but now Im afraid to do.

 

I wouldnt worry. Sure blasting water at connections is not the best idea, but most of them that would matter are not in the direct path of any car wash spray.
So yeah, its possible.....but its also very likely there was some other reason for this random persons issues. Even as simple as the connector had been undone at some point and simply was no longer weathertight.

Spray the salt away...the wires should outlast the frame on these things (sadly)

 

I think the more common issue is water intrusion from the sunroof drains going into the ECM and causing issues.
I believe that our 23 even has a note Automatic car washes about this in the manual.
I would personally not take it through an automatic wash. In fact, when I bought the GX and my Tundra, I specifically asked for them to be hand washed or not washed at all.
You could hook up a lawn sprinkler and place it under the car in a few areas for a few minutes at each location or use a undercarriage washer hooked up to a power washer if you have one.

 

The short answer is yes. Whether it's the lesser of all evils vs leaving the salt in place is debatable.

 

thanks for the response I do remember reading various people saying that their sunroof leaks down into their passenger footwell and that got something in the panels wet causing their electrical problems. I also don't plan on using a pressure washer underneath just a regular garden hose. It seems that the county has been extra exuberant under laying down of excess salt this year. I purchased my 2020 gx460 just last April and one of the first things I did was get under there and wire brush off and a surface rust anywhere that I can get to and I painted it. I know this was Overkill cuz it was only just surface rust on heavy duty solid steel control arms etc etc. But that's just the way that I am. My frame is very solid in that is one reason I purchased this particular vehicle. A lot of the other 2019, 2020 and even 21 gx460s were pretty well rusted underneath. Luckily mine had been undercoated by the previous owner. It was that heavy duty grease which I'm not a fan of but it was better than nothing.

 

Every fall I apply PB Blaster Surface Shield to the undercarriage of the GX and My Tundra. My Tundra is a 21 and still looks as good if not better than when it came off the lot. There are also other products such as Fluid Film, Wool Wax, Etc... that basically do the same as the Surface Shield. Typically I will wipe the undercarriage with a WD40 Soaked towel in the spring to removed the film and and any road grime from over the winter and then reapply in the fall. It takes me a few hours each time but the payoff is well worth it, plus it gives you time to evaluate everything you don't typically see on a daily basis.

 

Here are my 2 cents on this topic, i’ve been doing full underbody washes for years and have never had an issue, especially with my Lexus vehicles. In my region, underbody cleaning is a standard part of car culture most shops have lifts specifically for degreasing, removing road grime, and applying anti-corrosion coatings. Given the heavy rain and dirt we deal with, it’s practically a necessity once a year, once agaain its part of the car culture here, and considering you guys in the north have a more critical issue: Salt and corrosion, if I was living there I will do it even more often.

While electrical issues are a common forum fear, modern Lexus connectors are quite resilient if they are in good condition. That said, I would suggest a rules to keep things safe

Never use excessive force directly on electrical connectors or sensitive components like wheel speed sensors. It's about rinsing and degreasing, not sandblasting the wires.

I regularly put a small dab of dielectric grease on battery terminals, ground points, and the rear (wire-entry side) of accessible connectors like speed sensors. It’s an easy insurance policy against moisture intrusion, I do like maybe twice a year during my own inspections.

Ensure your underbody plastics and splash shields are intact. They are designed to deflect the spray from car washes and puddles.

In short: don't be afraid to get that salt off! It will do much more damage to your frame and brake lines over time than a controlled wash will do to your electronics.

 

two places that higher pressure water impacts undercarriage can be certain years puddle lamps and height sensors.
also when wet or damp and they cool they bring in moisture.
my opinion is it is worth it to wash the underside if in salt areas
connectors are sealed and qualification tested including water ingress

 

I had a minor issue with electrical for my headlamps post car wash but they got replaced (the car is 14 years old) and no more issues!