Test B: The Horn Is Always on

PINPOINT TEST B: THE HORN IS ALWAYS ON

B1-B6:

B7-B9:

Normal Operation
When the horn switch is pressed, the horn relay control circuit 460 (YE/LB) is grounded. The relay is then energized causing B+ voltage to be applied to circuit 6 (YE/LG), enabling the horns to sound. The horn relay B+ voltage and the horn relay switched voltage is supplied through circuit 1680 (OG/RD). The horn relay is controlled by ground circuit 460 (YE/LB) through the vehicle security module, the low tire pressure monitoring system (TPMS) module, and the horn switch. The powertrain control module (PCM) provides a ground for the horn relay through circuit 848 (DG/OG).

Possible Causes
- circuit 1 short to voltage
- circuit 6 (YE/LG) short to ground
- circuit 460 (YE/LB) short to ground
- horn relay
- horn switch
- clockspring
- TPMS module
- vehicle security module