Electrical System
366
On-Vehicle Charging System Checks
Troubleshooting No-Charge Condition:
Following is a step-by-step troubleshooting procedure. An experienced technician may use the schematic
and skip some of the procedure steps. See Figure 9-
12 for charging system schematic.
1. With engine not running, connect voltmeter across battery; voltmeter should indicate approxi-
mately 24 volts.
2. Leave voltmeter connected across battery; start engine and run at fast idle.
a. If voltmeter indicates 28 volts, battery is being charged. The problem is probably in the No-
Charge indicator light circuit. Check the fuse first, then troubleshoot circuit.
b. If voltmeter remains at 24 volts, the No-Charge indicator light is correct and the battery is not
being charged. Proceed to next step.
3. Connect voltmeter to alternator POS terminal.
a. If voltmeter reads 28 volts, troubleshoot for open circuit between alternator and battery
(check 325 amp fuse first).
b. If voltmeter reads low voltage, proceed to next step.
4. With the engine running, connect voltmeter positive lead to alternator F2 (ground) terminal and
negative lead to ground.
a. Voltmeter should read 0 volts.
b. If voltmeter reads a voltage, even if very small, a poor ground connection exists and must be
corrected before the system will operate properly.
5. Connect voltmeter to alternator F1 (field) terminal.
a. If voltmeter reads 28 volts, alternator is defective.
b. If voltage is 0 or less than 28 volts, proceed to the next step.
6. Switch the battery disconnect switch to the Off position. Unplug the harness connector from
the voltage regulator. Plug a break-out tool (Gillig part number 50-57843-000) into the voltage
regulator, and plug the harness connector into the break-out tool. This will allow you to test volt-
age regulator connections while the harness is connected and with the engine running. Refer to
Figure 9-12
. Connect voltmeter (+) lead to the NEG terminal of the break-out tool and voltmeter
(–) lead to ground.
a. Voltmeter should read 0 volts.
b. If voltmeter reads a voltage, even if very small, a poor ground connection exists and must be
corrected before the system will operate properly.
7. Connect voltmeter to regulator FLD terminal.
a. If voltmeter reads 28 volts and Step 5 indicates less than 28 volts, there is a wiring problem
in the field circuit between the alternator and regulator.
b. If voltmeter reads 0 or less than 28 volts, proceed to next step.
Summary of Contents for LOW FLOOR
Page 18: ...Specifications 18...
Page 58: ...Preventive Maintenance 58...
Page 110: ...Engine 110...
Page 138: ...Transmission Driveline Rear Axle 138...
Page 182: ...Suspension 182...
Page 260: ...Air System 260...
Page 420: ...Electrical System 420 Deutsch DT Series Connectors...
Page 421: ...Electrical System 421...
Page 422: ...Electrical System 422 Deutsch HD 10 Series Connectors...
Page 423: ...Electrical System 423...
Page 424: ...Electrical System 424 Deutsch HD 30 Series Connectors...
Page 425: ...Electrical System 425...
Page 442: ...Heating Air Conditioning 442...
Page 492: ...Body and Interior 492 Figure 11 33 USSC Seat Assembly...
Page 493: ...Body and Interior 493 Figure 11 34 USSC Seat Suspension Assembly...
Page 495: ...Body and Interior 495 Figure 11 37 Seat Air Connections...