Parasitic Load Testing
TOOLS REQUIRED- J 38758 Parasitic Load Test Switch Tool
- J 39200 Digital Multimeter
NOTE: The parasitic draw test switch should never be turned to the OFF position with the engine running. Damage could occur to the attached ammeter or the vehicle electrical system.
Caution: Refer to Battery Disconnect Caution in Cautions and Notices.
1. Disconnect the negative battery cable.
2. Connect the J 38758 male end to the negative battery terminal.
3. Turn the test switch knob to the OFF position.
4. Connect the negative battery cable to the J 38758 female end.
5. Turn the J 39200 to ON.
6. Road test the vehicle with all of the accessories on.
7. Turn the ignition to LOCK.
8. Remove the ignition key.
9. Set the ammeter to 10 A.
10. Connect the J 38758 to the test meter terminals with alligator clips.
11. Turn the J39200to OFF.
Important: Always turn the test switch tool knob to the ON position before removing each fuse to maintain continuity in the electrical system and to avoid damaging the ammeter due to an accidental overload (i.e. opening door to change a fuse, etc.).
12. Check the current reading:
- A reading below 25 mA is acceptable.
- If the current reading is at or below 2 A, perform the following steps:
12.2.1. Turn the J39200 to ON.
12.2.2. Switch the ammeter to a lower scale.
12.2.3. If necessary, use a more accurate meter.
12.2.4. Turn the J39200to OFF. If the reading is above 25 mA .
- A zero reading indicates a problem with the meter, the scale being used, or a connection.
- If the reading is above specifications, perform the following:
Parasitic Load Examples:
12.4.1. Remove the system fuses one at a time until current draw returns to a value less than or equal to the specifications. Refer to Parasitic Load Examples Table above.
12.4.2. Perform steps 11 and 12 above each time a fuse Is removed.
- A reading above 100 mA may suggest the following:
- Grounded wires
- Sticking relays
- A light is ON.
Refer to Repair Procedures in order to make necessary repairs.
13. When the cause of the current draw has been located and repaired, perform the following:
13.1. Repeat steps 11 and 12 above in order to verify the repair.
13.2. Turn the J39200 to OFF.
13.3. Remove the J 38758.
13.4. Connect the negative battery cable.
Tighten
Tighten the negative battery cable to 15 N.m (11 lb ft).
NOTE: Refer to Fastener Notice in Cautions and Notices.