One problem related to horn assembly has been reported for the 1999 Toyota 4Runner. The most recently reported issues are listed below.
Abs light ;po500 code speed sensor a speedometer not working, wont shift into gear with abs light on windows malfunction and all electric windows stopped working possibly due to same abs circuite as noticed same exact timeframe. Apart from that prior malfunctions include airbag light stays on needs restting from dealer and also horn does not operate. Missing/no factory installed fog lamps --dealer wants over 1,200. 00 for 2 basic fog lamps from their parts dept.