CarlosSaeed

This is my first time posting on this forum.
There was heavy rain last couple days here and some water has somehow made its way beside the trunk fuse box. Since then my trunk latch keeps trying to open itself and is making a horrendous noise. The fuel cap also opens along with it.

Another issue I am facing is my High beams are turned on and wouldnt shut offf even though the high beam indicator on yhe dashboard is off.
Pushing on the light switch stick to engage or disengage the high beam has no effect neither does the high beam indicator come on or off.

Similar issue with my tail lights. They are also turned on but surprisingly when braking, the brake lights do not come on.
I’ve tried to search for the problem on this forum before making this thread but couldn’t find anything.

My temporary fix was to remove the no. 10 fuse from the trunk fuse box to cut power to the trunk and fuel cap. This also caused my fuel gauge to stop working which i assume is also connected to the same fuse.

I need your help to diagnose the problem since I am trying to do it DIY.
Also sorry for the long post, i wanted to give as much information as possible.

Car: LS430 2006 CL (no air suspension)

YoshiMan

How certain are you that water has made its way into the electronics? Do you actually have visible water in them? If so, I would work on trying to get the moisture out of those components first, and then try and find where that water was getting in and correct the issue.

If you actually find moisture in the electrical connectors, and such, you can drive it out with little shots of WD40, because it displaces water and does not conduct electricity. Just wipe everything down afterwards so it doesn't attract dust and make a mess. Probably the first line of attack before you consider replacing things.

CarlosSaeed

Yes there was a puddle in the space beside the trunk fuse box which I removed most of it using a cotton cloth. I’ve located the culprit to be the rear tail light gasket since ive had a dent removed from that area. It could be that the denter who fixed it dint do a good job. Regarding the moisture, I will definitely try to spray WD-40 and get rid of it all.

I still do not understand what could be the problematic part.

alextv

Do not use wd40 as that will leave a residue and use air instead and completely dry out with heat or sun. Look for any corrosion and clean. There are several threads on here where some have cleaned and others have had to replace the whole fuse box. The part is the whole fuse box.

CarlosSaeed

thank you i will use air and heat gun to dry it out
what i do not understand is if the whole fuse box was ruined wouldnt that mean none of the electronics connected to that fuse box would work? In my case its the opposite and only the fuel cap and trunk lid mechanism is malfunctioning (stuck open/trying to open)

alextv

It all depends on what is being shorted out in box. This is a well known issue when taillight gasket leaks.

YoshiMan

I guess I should add that the WD40 method is more for an emergency and should be flushed out afterwards with electronics cleaner, and that it should only be used on connectors, not so much the fuse panel itself unless it's a last ditch effort.

And alot of the times water intrusion doesn't automatically mean that the electronic part is ruined per se, as a lot of electronics will work perfectly fine after being dried out. (Ask me about my original Gameboy I had on me when I fell through thin ice when I was a kid. The thing still works perfectly fine to this day)

And there is probably just water causing a short on those particular circuits. I had an issue with the under hood fuse/relay panel in my 08 Ridgeline, and it caused some really screwy things to happen with the wipers and dashlights, even though everything else in the box was still functioning properly. On that particular instance I just replaced the box with a used one, because it was on backorder from Honda, and the particular relays that were going bad were in a sealed part of the box that were not serviceable.

So yes, the box was "bad" but the car was still was functional for the most part.

CarlosSaeed

Update:
I used a can of air and hair dryer as that was the only thing close to a heat gun i could find and dried out the whole trunk, fuse box.
The headlight high beam issue I had got fixed, so did the fuel door being stuck open.
Now the problem is that even after putting the fuse back in, the fuel gauge is still broken and reading empty even though i put like 30l of fuel. Also the trunk closing mechanism seems to have given out and its working at all now. Along with that my tail lights have shorted out with no reverse lights either but somehow the indicators still work.
It seems like i need a new pair of tail lights
As for the fuel gauge, i still have to remove the back seats to access the sensor on top of the fuel tank.

alextv

Anything that changed with the water damage that is not working now is very likely still fuse box related. You did take the fuse box completely apart to dry correct? If everything is 100% dry and you don't see any visible corrosion top and bottom while apart it could still be an open trace or hidden corrosion. Voltmeter and schematic would verify.

YoshiMan

Probably moisture trapped in the innards that no amount of compressed air is going to remove.

Since it's likely trashed, why not try the WD-40 method before replacing it?