Twr Length Sensor Two Value Out Of Range High - JLG 1250AJP Troubleshooting Manual

Note Pretest Instructions
1.367.4 Disconnect BLAM J3 X088].
Turn on machine.
1.367.5 Unclip sensor #1 cable
from boom. Observe resis-
tance between tower boom
length sensor 1 (Top) pin A
[X093.A.pin] and pin C
[X093.C.pin].
1.367.6 Disconnect tower boom
length sensor #1 (top)
[X093] and BLAM J3 [X088]
1.367.7 Disconnect tower boom
length sensor #1 (top)
[X093] and BLAM J3 [X088]
1.367.8 Disconnect tower boom
length sensor #1 (top)
[X093] and BLAM J3 [X088]

1.368 TWR LENGTH SENSOR TWO VALUE OUT OF RANGE HIGH

Flash Code: 8-4
Tower length sensor 2 (bottom) value out of range high. The BLAM module is reading a value above 675.4" for the calibrated
tower length sensor #2 (bottom). This sensor should always read between 299.4" and 675.4". This could be caused by a
mechanical problem with the sensor or cable, the sensor ground wire being broken, or a sensor failure.
Note Pretest Instructions
1.368.1
1.368.2 Disconnect tower boom
length sensor #2 (top)
[X094]
1.368.3 Turn on machine. Discon-
nect tower boom length sen-
sor #2 (bottom) [X094]
1.368.4 Turn on machine. Discon-
nect BLAM J 3 [X088]
3128411
SECTION 1 - FAULT DICTIONARY AND SELECTED TROUBLESHOOTING
Test
I s there about 5VDC between BLAM J3 pin 7
[X088.7.pin] and pin 9 [X088.9.pin]?
Have second person slowly walk cable out
and back completely. The sensor cable
extends 400 inches (33' 4"). (Do not allow
cable to retract in an uncontrolled or rapid
manner. This will break the sensor.) Does
resistance change smoothly and consistently
up to 5000 Ω ± 500 Ω and back?
Is there a short between tower boom length
sensor #1 (top) socket C [X093.C.soc] or
BLAM J3 socket 8 [X088.8.soc] to battery
negative [X117]?
Is there continuity between tower boom length
sensor #1 (top) socket C [X093.C.soc] and
BLAM J3 socket 8 [X088.8.soc]?
Is there a short between tower boom length
sensor #1 (top) socket C [X093.C.soc] and
socket B [X093.B.soc]?
Test
Is the tower boom length sensor #2 (bottom)
[X094] securely mounted to the machine and
is cable free to move?
Does the tower boom length sensor #2 (bot-
tom) connector [X094] have moisture, dam-
age or corrosion?
Is there about 5VDC between tower boom
length sensor #2 (bottom) socket A
[X094.A.soc] and socket B [X094.B.soc]?
Is there about 5VDC between BLAM J 3 socket
7 [X088.7.pin] and pin 9 [X088.9.pin]?
1250AJP
Result Corrective Action
Yes Repair/replace harness between BLAM J3
[X088] and tower boom length sensor #1 (top)
[X093]
No Replace BLAM
Yes Go to step 1.367.6
No Replace tower boom length sensor #1 (top)
[X093]
Yes Repair/Replace harness between tower boom
length sensor #1 (top) socket C [X093.C.soc],
BLAM J3 socket 8 [X088.8.soc] and battery neg-
ative [X117]
No Leave tower boom length sensor #1 (top) [X093]
and BLAM J3 [X088] disconnected. Go to step
1.367.7
Yes Go to step 1.367.8
No Repair/Replace harness between tower boom
length sensor #1 (top) socket C [X093.C.soc],
BLAM J3 socket 8 [X088.8.soc].
Yes Repair/Replace harness between tower boom
length sensor #1 (top) socket C [X093.C.soc]
and socket B [X093.B.soc]
No Reprogram/replace BLAM
Result Corrective Action
Yes Go to step 1.368.2
No Repair as needed
Yes Repair as needed
No Keep tower boom length sensor #2 (bottom)
[X094] disconnected. Go to step 1.368.3
Yes Go to step 1.368.5.
No Keep machine in same state. Go to step 1.368.4
Yes Repair/replace harness between BLAM J3
[X088] and tower boom length sensor #2 (bot-
tom) [X094]
No Replace BLAM
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