I also found a short drain trough formed into the firewall to let water drain and not enter the fresh air (vent) behind the a/c at the firewall. It was clogged with leaves and debris and the water would come in under the dash and behind the carpet that goes up toward the lower dash. It was a...
There are a lot of places water can enter the cab. Go ahead and remove the sun visors and headliner. If your truck has a sunroof you will see a drain tube in each corner. The sunroof housing is larger than the part that opens, So, the rear drains are in the back. If the drains are flowing freely...