One problem related to horn assembly has been reported for the 2003 Toyota Sienna. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2003 Toyota Sienna based on all problems reported for the 2003 Sienna.
Design defect on horn for 2003 Toyota Sienna. 1. Only one out of the two horn bottom contact plates is electrically connected. 2. The steering wheel is not directly grounded by the spiral cable. Ground from spiral cable is used for the cruise control and remote radio control. The ground for the horn is only indirectly grounded through the shaft. I just haven't used the horn until recently. Horn is not reliable. Some times it doesn't work. Especially when pressing on the left side of the horn pad. Many people have been complaining of horn malfunction on Toyota car owner boards and Toyota not being able to repair it properly (replacing spiral cable and relay), on my van, the connection to the relay is missing (never installed) on the left side contact plate and active ground is missing. I have not figured out how to fix these safety defects.
| Instrument Panel problems | |
| Computer Failure problems | |
| Horn Assembly problems | |
| Battery Cable problems |