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Sevcon Troubleshooting
Page 9
Electrical Troubleshooting
Test 3. THE VEHICLE RUNS IN ONE DIRECTION ONLY
TEST 3.5
Disconnect the batteries and remove wires from
the B-, F1, and F2 terminals on the controller.
Using the diode test function on your meter, connect
the positive lead to the B- terminal on the controller.
Connect the negative lead to the F1 terminal on the
controller.
The test should show the presence of a diode
(approx 0.5v).
If the test is good, then skip ahead to test
#3.6.
If the test is open or shorted then one or both
directional FET’s are shorted and the
controller must be replaced.
TEST 3.6
Disconnect the batteries and remove wires from
the B-, F1, and F2 terminals on the controller.
Using the diode test function on your meter,
connect the positive lead to the B- terminal on
the controller.
Connect the negative lead to the F2 terminal on
the controller.
The test should show the presence of a diode
(approx 0.5v). If the test is open or shorted
then one or both directional FET’s are
shorted and the controller must be replaced.
Test 3.1:
Close the seat switch, turn the key switch ON and
wait 1-second until the Isolator contactor closes.
If the vehicle runs in reverse only then skip
ahead to test #3.3.
Place the forward and reverse switch in the
FORWARD direction.
Test the voltage at pin #2 on the 12 pin logic card
connector.
If the voltage is low, then skip ahead to test
#3.2.
If the voltage is high, then skip ahead to Test
#7.
TEST 3.2:
Test the voltage at pin #3 on the 12 pin logic card
connector.
If the voltage is high, then skip ahead to test
#3.3.
If the voltage is low, then skip ahead to Test
#7.
TEST 3.3:
Place the forward and reverse switch in the
REVERSE direction.
Test the voltage at pin #3 on the 12 pin logic card
connector.
If the voltage is low, then skip ahead to test
#3.4.
If the voltage is high, then skip ahead to Test
#7.
TEST 3.4:
Test the voltage at pin #2 on the 12 pin logic card
connector.
If the voltage is high, then it is likely that the
internal directional control transistors have
failed, test the transistors at Test 3.5 and 3.6.
If the voltage is low, then skip ahead to Test
#7.
Stop, do not continue. Reaching this point
indicates a failure in the Sevcon power unit
or an error was made during testing. Confirm
all previous tests were performed correctly
before replacing the Sevcon power unit.
STOP
Summary of Contents for B0-248-36
Page 2: ......
Page 6: ...TAYLOR DUNN...
Page 76: ...Maintenance Service and Repair Steering Page 22 Exploded View of Steering Gear...
Page 102: ...TAYLOR DUNN...
Page 138: ...TAYLOR DUNN...
Page 144: ...TAYLOR DUNN...
Page 156: ...TAYLOR DUNN...
Page 159: ...Sevcon Troubleshooting Page 3 Electrical Troubleshooting Identifying Your Controller...
Page 178: ...TAYLOR DUNN...
Page 210: ...Illustrated Parts Parts Page 2 Part number not available at time of printing Front Axle...
Page 212: ...Illustrated Parts Parts Page 4 Part number not available at time of printing Steering Knuckle...
Page 214: ...Illustrated Parts Parts Page 6 Part number not available at time of printing Front Brakes...
Page 216: ...Illustrated Parts Parts Page 8 Part number not available at time of printing Steering Linkage...
Page 228: ...Illustrated Parts Parts Page 20 Part number not available at time of printing Rear Brakes...
Page 230: ...Illustrated Parts Parts Page 22 Part number not available at time of printing Brake linkage...
Page 234: ...Illustrated Parts Parts Page 26 Part number not available at time of printing Motor...
Page 278: ...Illustrated Parts Parts Page 70 Part number not available at time of printing Hitches...
Page 279: ...Illustrated Parts Parts Page 71 Part number not available at time of printing...
Page 280: ...Illustrated Parts Parts Page 72 Part number not available at time of printing...
Page 281: ...APPENDIX A Special Tools...
Page 290: ...Model B 1 00...
Page 291: ......