Service Manual

SECTION 6 - TROUBLESHOOTING
3121228 – JLG Lift – 6-25
Code 21 - Beacon - Disconnected
Check For These Obvious Conditions First:
• Is machine equipped with flashing amber beacon light.
Code 22 - Horn - Short Circuit
Check For These Obvious Conditions First:
• Damaged wiring in the horn wiring harness or a damaged horn unit.
Table 6-22. Code 21 - Beacon - Short Disconnected
STEP ACTION SPEC YES NO
1. Is machine equipped with a flashing amber beacon light.
— Go to Step 3 Got to Step 2
2. At the Ground Control Module enter the programming mode, check if the
Beacon light open circuit detection is enabled.
—Disable ItReplace Ground
Control Module
3. Check voltage at the P1 connector on the Ground Control Module between
pin-12 and pin-5. Is reading within specification?
2 - 4 V DC Replace Ground
Control Module
Go to Step 4
4. Remove the wire terminals at the beacon, check continuity of each of the
wires from pins-12 and 5 on the P1 connector to the beacon end.
— Replace the
Beacon
Repair or
Replace Wiring
Table 6-23. Code 22 - Horn - Short Circuit
STEP ACTION SPEC YES NO
1. At the Ground Control Module, P1 connector, check the voltage across
pins-14 and 7 to the horn. Is reading within specification?
0 - 2V DC Go to Step 2 Replace Ground
Control Module
2. Remove the wire terminals at the horn, check continuity of each of the wires
from pins-14 and 7 on the P1 connector to the horn end.
— Replace the
Horn
Repair or
Replace Wiring