Parasitic Draw - Test Clarifications
Parasitic DrawTest Clarifications
The Parasitic Draw Test procedures in S/B 92-001, "Charging System Testing," show how to connect the ammeter in series without losing power to the clock and radio. But apparently our pictures weren't worth a thousand words. Here are some more words to make up the difference.
To measure parasitic draw, make sure the doors are closed, all electrical components are off, and the ignition switch has been turned off for at least five minutes (for passive belt timers to reset). Loosen, but do not remove, the negative battery terminal. With your ammeter on the 10 A scale, touch the negative ammeter lead to the negative battery post and touch (or connect) the positive ammeter lead to the negative battery cable terminal.
Now, without breaking the contact between the test leads, battery post, and battery cable, carefully lift the negative cable off the negative post. The ammeter is now in series with the electrical system and is reading parasitic draw.
If the reading is less than 0.2 A (200 mA), put the cable back on the post, change the ammeter range and leads to 200 mA, and lift the cable off the post again to get a more precise reading. If the reading exceeds the specs in the S/B, isolate the source of the draw by removing fuses and disconnecting components as described in the bulletin.