WARNING: This page is about a different car, the 2007 Toyota Tacoma. However, it is still accessible from the selected car via links, so may be relevant.
HORN SERVICE DATA
Fuse (HORN)
Standard
Below 1
Relay (HORN)
Standard
10 k or higher
Resistance (3 - 5)
Below 1 (When battery applied to terminals 1 and 2)