1. Connect the battery and close the seat switch.
Coil Pulsing
2. Turn the key to ON and release the parking brake.
1. Disconnect the battery and discharge the head capacitor.
3. Select a direction and rapidly depress the accelerator pedal all the way to the floor.
2. With the contactor coil leads connected, set the multimeter to the 200 volt DC range.
4. Measure and record the time it takes the bypass contactor to close. This should be 1.0 to 2.5 seconds after the accelerator is fully depressed.
3. Connect the multimeter negative lead to the negative coil terminal Y and the meter positive lead to the coil positive terminal X wire #38. 4. Connect the battery and activate the controls necessary for the contactor to be activated.
5. If the recorded value from Step 5 is less than 1.0 seconds, the logics may need to be replaced. (During normal operation, this time will vary with the load on the truck.)
5. After the contactor activates, the multimeter must indicate 18 to 35 volts. If the voltage is not correct and the contactor passed the Coil Resistance test, the logics must be replaced.
6. If the recorded value from Step 5 is more than 2.5 seconds, check the bypass contactor tips for free movement. Check wiring for bad connections.
Contactor Tips E345
NOTE: The bypass contactor will not close if the accelerator linkage is not adjusted correctly. It also may not close if programmable feature “5” (Top Travel Speed) is not set to maximum.
Contactor Components
WARNING Battery voltage and high amperage are present. Injury to personnel is possible. Disconnect the battery and discharge the head capacitor (HEAD CAP) before any contact is made with the control panel.
Checking Contactor Tip Gap
1. Disconnect the battery and discharge the head capacitor.
Coil Resistance
2. Visually inspect the tips to verify that they are not welded, melted, burned or pitted.
1. Disconnect the battery and discharge the head capacitor.
3. Press and release the tips quickly to verify that there is no bonding.
2. Disconnect all leads to the X and Y terminals of the coil.
4. Visually inspect the contactor assembly. Verify foreign objects don’t interfere with normal contactor operation.
3. Set the multimeter to 200 ohm range.
5. Check contactor tip gap with a feeler gauge as shown. Refer to the Specifications section for correct settings.
4. Measure the resistance of the coil at the X and Y terminals. It must be within specifications. See Component Measurements in the Specifications section. 5. If the coil is not within specifications, the contactor assembly will have to be replaced.
MicroCommand Control System
115
Testing And Adjusting
