Operation CHARM: Car repair manuals for everyone.

Pinpoint Test 2

PINPOINT TEST 2: THE HORN IS ALWAYS ON

Step 1:




Step 2-Step 5:




Normal Operation
The horn relay control voltage and the horn relay switched voltage circuits are supplied by the smart junction box (SJB) fuse 13 (15 A) through circuit (GY/R). The horn relay (part of the SJB) is controlled by circuit (Y/R) through the clockspring to the horn switch (part of the steering wheel). When the horn switch is pressed, the horn relay control circuit (Y/R) is grounded through the steering wheel switch harness (part of the steering wheel). The horn relay is then energized causing voltage to be applied to circuit (B/W), enabling the horn to sound. Ground to the horn is supplied through circuit (B/GY).

Possible Causes
- Circuit (Y/R) short to ground
- Circuit (B/W) short to voltage
- Clockspring
- Horn switch (part of the steering wheel)
- SJB