A couple years ago, I woke up on a rainy morning to a dead rig. Battery drained. When I charged up the battery, the tail lights stayed on. It was bizarre. Until I noticed that there was water on the floor by the cowl under the steering wheel. The rain had leaked into the cabin behind the dash and shorted out the electricals. How was the water getting into the rig? I poked around abit, but found nothing definitive. Until I had more time and focus, I draped a tarp over the driver side of the LC when it rained.
It rains so seldom in Southern California that I forgot about the problem until it rained the next year. Truck’s tail lights came on spontaneously in the rain. Out came the tarp.
My ih8mud research suggested that the drains at the corners of the sunroof could be clogged, causing water to get into the cabin behind the DS dashboard. I had also noticed that the rubber gasket between the windsheild and the body had started to loosen at the bottom DS corner. I noticed first when the blast of those high speed dryers at the end of the Costco drivethrough car wash hit the rig’s windshield. The loosening end of the gasket would wriggle a little more loose. I tried to fix it by indelicately shoving it back into place, but my attempt was visibly imperfect. Where the gasket should have been smoothly in place, it was visibly warping and bugling. Maybe water was getting in there?
Today, I without a cloud in sight, I tackled this mystery.
First, I grabbed a length of plastic weed eater line and fed it into the sunroof’s forward DS drain hole. It went in about 5.5 feet, and it went in about the same in the forward PS drain hole. I concluded that the drains were clear. (There’s been no moisture on the PS side of the cabin.)
Then, I took the wife’s watering can and carefully poured water down the sunroof’s forward DS drain. I didn’t measure how much went in, but I did grab this video of how it came out underneath the truck.
THis surprised me. I had expected the water to drain from one of those plug holes we see under the rig. I crawled under the rig to look at the plugs. They appear to be inserted from above, but I was able to punch one out (carefully) and feel around inside with a finger. It was damp, and there was nothing above but space. Nothing was blocking water flow, anyway.
I ran some more water down the DS sunroof drain and it leaked out in the same fashion. I can only conclude that the water is not getting in because of forward DS or PS the subroof drains.
So I returned to that gasket on the DS lower corner of the windshield. My fingers were almost too big, but I tried to work that gasket further back into place manually, sometimes with the help of a stiff, flat paint scraper. After a few minutes of massaging the gasket in this way, it looked a lot better. Now I can either wait for the next rain, or I can test it by putting a sprinkler on the hood and letting it run for a while. What should I do?