TEST OR INSPECTION
ELECTRICAL SYSTEM - CONT
Using semitrailer electrical schematic (figure FO-1), check for open circuit in wiring or terminal board.
If wiring or terminal board has a ground or open circuit, repair or replace as required.
At gooseneck component assembly, using an electrical tester (multimeter) (item 17, appx. B), check
resistors and diodes for open circuit. Remove six bolts and carefully remove gooseneck component
assembly from gooseneck. Turn component assembly upside down for accessibility (para. 4-22).
a. Probe pins J1-B to J2-3; results should reflect 7 ohms.
Probe pins J1-J to J2-5; results should reflect 7 ohms.
Probe pins J1-E to TB2-1; results should reflect 2 ohms.
b. Probe terminal boards TB2-1 to TB2-2; results should reflect continuity in one direction. Reverse
leads and results should reflect resistance in other direction.
Remove Jumper wire from terminal board TB2-3 and probe pins TB2-1 to TB2-3. Results should
direction. Reinstall jumper wire to pin 3.
DIM OR FLICKERING LIGHTS
Inspect for proper output from tractor.
Repair or replace any defects found as required.
Check light assemblies for corrosion, missing parts, and burned bulbs.
Using semitrailer electrical schematic (figure FO-1) and multimeter (item 17, appx. B), check for
intermittent ground or open circuit.
If wiring is defective, repair or replace as required.