Repair manual

RD 27 Troubleshooting the Engine Start System
wc_tx000948gb.fm 35
3.4 Checking the Key Switch
Prerequisites  Fully-charged battery
 Multimeter
Procedure Follow the procedure below to check the key switch.
1. Remove the control panel (a) from the steering column.
2. Locate the key switch. Note it’s terminals are labeled: BAT, START, CONTROL,
AID, and RELAY.
3. Measure the voltage between terminal BAT (brown wire) of the key switch and
ground.
Is 10–12.5 VDC measured?
4. Turn the key to the START position and hold it there. Measure the voltage
between terminal RELAY and ground.
Is 10–12.5 VDC measured?
5. Turn the key to the START position and hold it there. Measure the voltage
between terminal START and ground.
Is 10–12.5 VDC measured?
6. Turn the key to the GLOW PLUG position and hold it there. Measure the voltage
between terminal CONTROL and ground.
Is 10–12.5 VDC measured?
The key switch has now been checked.
If the problem has not been resolved, continue with Checking Start 2 Relay.
Yes ____ No ____
Continue. Check/repair the brown wire between the key switch fuse and the
key switch.
Yes ____ No ____
Continue. The key switch has failed; replace it.
Yes ____ No ____
Continue. The key switch has failed; replace it.
Yes ____ No ____
The key switch is OK. The key switch has failed; replace it.