John Deere stx38 User Manual

Page 144

Advertising
background image

ELECTRICAL

CIRCUIT OPERATION AND DIAGNOSIS

4 - 60

3/21/97

HEADLIGHTS CIRCUIT DIAGNOSIS STX38 (SN 210001— ) & STX46

NOTE: Fusible link (F1) 201 orange wire is designed to melt internally. You cannot see that the fusible link is bad

by looking at it, test for battery voltage at 200 red wire at key switch terminal B to verify fusible link is good.

Test Conditions:

• Key switch in RUN position

• Headlights switch ON (engaged)

• Meter negative (-) lead on battery negative (-)

terminal

• Meter positive (+) lead on numbered test point

Test/Check Point

Normal

If Not Normal

1. Battery positive terminal

11.8—13.2 volts

Test battery

2. Key switch terminal B (200 red

wire).

Battery voltage

Check battery cable connection,
fusible link 201 orange and 200 red
wire.

3. Key switch terminal A (400

yellow wire).

Battery voltage

Replace key switch.

4. PTO switch 400 yellow wire.

Battery voltage

Test 400 yellow wire.

5. Headlights switch 450 yellow/

white wire.

Battery voltage

Replace 450 yellow/white wire.

6. Headlights switch 451 yellow/

white wire.

Battery voltage

Replace headlights switch.

7. Headlights kit harness yellow

wire.

Battery voltage

Replace 451 yellow/white wire.

8. Headlights kit light sockets red

wires.

Battery voltage

Replace headlights kit light sockets
and harness.

9. Headlights kit harness black

wires and tractor harness 120
black wire at W2 engine
ground.

Battery voltage

If ground circuit is good, replace
bulbs.

Advertising