From day one I did not feel as though the horn on my truck was loud enough. Sounded wimpy for a truck. Horns are first and foremost a safety device, to be used sparingly. When used properly, horns can prevent accidents. This would assume of course that other drivers would actually be able to HEAR your horn. The horn needs to be loud enough to keep a tractor-semitrailer from drifting into your lane at interstate speeds.
I planned on upgrading and replacing my stock horn with a louder aftermarket horn, like I did on my 1992 z32. However, I found out this little mod made the horn noticably louder, took about three minutes, and at a cost of zero dollars.
The horn can be seen by looking through the front grill of the truck. To get to the horn, open the hood. There was a solid metal cover attached to and completely blocking the horn outlet or "trumpet." I removed this cover or baffle and the horn is noticably louder now, enough so that I don't want a new horn anymore.
The hood is open, looking down between the radiator and the grill, the horn is circled. The front of the truck is at the bottom of the picture. Horn is under the hood safety latch.
Since I did not have to remove the horn for this mod, here is a pic of a typical electric "snail" horn. On my truck, there was a solid metal cover or baffle covering the outlet or trumpet of the horn shown by the arrows. The baffle was easily pried off with my fingers.
Here is the metal baffle that was covering the horn outlet, held in place by built-in clips on the top and bottom. This piece came off with surprisingly little effort.
I put a 10mm wrench on the mounting bolt on the back of the horn, loosened it, and turned the horn so the trumpet (outlined in green) faced down toward the ground. This would theoretically keep any water from collecting in horn. The wiring harness to the horn can be seen behind the wrench but I did not have to touch that. The horn sits in front of the radiator which is on the right side of the picture.
Even my girlfriend immediately commented that the horn was noticably louder. I stood in front of the truck and had her beep the horn before and after the cover was removed and thought the difference was obvious.
A couple of other members on a Tacoma forum to which I belong reported no long-term issues with removing this baffle. I will post back here if any problems ever show up. I have seen and installed many electric snail horns of this type, including having them fully exposed to the elements on my motorcycle and boat, and never had a problem with the trumpet being open and not covered.
Air horns are much louder, but can literally cause hearing damage to someone standing too close to the front of your vehicle. Plus, on many airhorns there can be a split-second delay from the time the horn buton is pressed and the horn sounds. At highway speeds, that can translate into a significant number of feet that could be the difference between becoming involved in a collision or not.