JLG 15/20MSP Service Manual - Manual (Page 147)

SECTION 6 - TROUBLESHOOTING
3121231 – JLG Lift – 6-27
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 6-25. 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 It Replace 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 6-26. 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