(c) If no cutout is used and connections between the generator (or motor- generator) and the battery are made by closing the ignition or starting switch, such as is the case on Delco and Dyneto motor-generators, and some Delco generators, disconnect from the generator or motorgenerator the wire that goes to the ammeter or indicator. If this causes the voltmeter pointer to return to the "0" line, the switch which connects the generator or motor-generator to the ammeter or indicator is defective. If the voltmeter pointer does not return to the "0" line, replace the wire and consult paragraph (d).
(d) Defective Starting Switch. Disconnect from the starting switch the cable that goes to the battery. If one or more smaller wires are connected to the same terminal as the heavy cable, disconnect them also and hold their bare ends on the bare end of the heavy cable. If this causes the voltmeter pointer to return to the "0" line, the starting switch is defective. If the voltmeter pointer does not return to the "0" line, replace the cable and wires on the starting switch terminal and proceed as follows:
Defective Switches. See that the ignition and lighting switches are in their "OFF" positions. If they are not, open them and see if the voltmeter pointer returns to the "0" line. If it does, you have found the trouble. If it does not, disconnect from the switch (or switches, if there are separate lighting and ignition switches), the feed wire which supplies current to the switch from the battery. If this causes the voltmeter pointer to return to the "0" line, the switches are defective. If the pointer does not return to the "0" line, replace the wires on the switch and consult the next paragraph.
If there are other switches which control a spot light, or special circuits, such as tonneau lamps, or accessories, such as gasoline vaporizers, electric primers, etc., make the same tests on these switches. If no trouble has been found, see paragraph (e).
(e) Grounds or Short-Circuits in Wiring. Disconnect from each terminal point in the wiring system the wires which are connected together at that point. Also remove fuses from the fuse blocks. If the voltmeter pointer returns to the "0" line when a certain wire or fuse is removed, there is a ground or short-circuit in the wire or in the circuit to which the fuse is connected.
(f) Turn on the Lights. Remove the voltmeter and complete the battery connection. Note how much current is indicated on the ammeter mounted on the instrument panel of the car as the different lamps are turned on. In each case the ammeter should indicate "discharge." Should the ammeter indicate "charge" the battery connections have been reversed, or the ammeter connections are reversed. The driver will tell you whether the ammeter has been reading "charge" or "discharge" when the lamps were turned on. This is a good way to check your battery connections.
If the car has no ammeter, or has an indicator which is marked "ON" or "OFF," or "Charge" or "Discharge," an ammeter may be connected in series with the battery by disconnecting the cable from the positive battery terminal and connecting the ammeter to the cable and to the terminal, and the readings obtained from this meter.
The amperes indicated on the ammeter should be the greatest when the main headlamps are burning bright. By comparing the readings obtained when the different lighting combinations are turned on, it is sometimes possible to detect trouble in some of the lighting lines.
3. Start the Engine. Before you do this, be sure that the cables are connected directly to the battery terminals, and that no ammeter or voltmeter is connected in series with the battery, as the heavy current drawn by the starting motor would ruin the instruments very quickly. An ammeter may be left connected in series with the battery, providing that a switch is used to short-circuit the meter while starting the engine. A meter having a 500 ampere scale may be left connected in series with the battery while the engine is being started, but for the tests which are to be made a 25 ampere scale should be used.
The engine should start within ten seconds after the starting switch is closed. If more time than this is required, carburetor adjustments, position of the choke lever, etc., should be looked after. Continued cranking of the engine will run the battery down very quickly, and the chances are that the car will not be run long enough to allow the generator to recharge the battery. Make whatever adjustments are necessary to reduce the cranking time to ten seconds, or advise the owner to have them made, warning him that otherwise you will not be responsible if the battery runs down very quickly.