One problem related to wiring has been reported for the 2006 Toyota Tundra. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2006 Toyota Tundra based on all problems reported for the 2006 Tundra.
I bought this Toyota brand new. I have been worried about the horn on my Toyota not being very loud. This is a safety issue. I have taken the horns off and bought another set of horns that are 2 wire for connection. Your horn is one wire and the frame of the horn is the ground. Finally I figured out, after the switch, why your Toyota horn is not working or is working poorly. Your design relies on the case of the horn grounding to the frame of the vehicle for the negative pole. The whole horn is painted so there is little chance of grounding to negative pole. The mounting bracket is painted, further hampering the negative connection. The mounting bolt and frame are painted making a negative connection almost impossible. I believe this is a serious design flaw. The horn is required and should be working very well and not marginally. The horn on the Toyota is marginally safe.