4-13. TROUBLESHOOTING (CONT)
TEST OR INSPECTION
HYDRAULIC SYSTEM - CONT
STEERING PRESSURE INDICATOR DOES NOT LIGHT
Check that power is supplied from tractor to running lights.
If steering pressure indicator fails to light, refer to symptom 31 and check tractor/semitrailer electrical.
Check that steering pressure indicator light bulb is working.
Using a 12 Vdc battery and jumper leads, connect leads to poles of bulb. If bulb is defective, replace
Check wiring to pressure switches.
Check jumper wires to four pressure switches and check wiring harness W3 for breaks, pinched or
Using an electrical tester (multimeter) (item 17, appx. B), check for defective pressure switch on
Make sure the tractor/semitrailer is coupled and running lights are turned on.
If checking more than one pressure switch, recharge the steering circuit between
each check by running the APU and operating the steering valve for 10 seconds in
both directions until indicator light goes out.
a. Using an ohm meter, connect leads to poles of pressure switch PS5. Reading on meter should
be infinity (open). Check operation of pressure switch PS5 by slightly opening aft bleed valve on
curbside platform cylinder. Allow only residual pressure to be bled from cylinder. Once pressure
is relieved from cylinder, close bleed valve and check indicator light. Indicator light should be lit
and ohm reading should be zero (closed). If indicator light is not lit or ohm reading is not zero,