Proheat X45–School Bus - Manual (Page 83)

PROHEAT INSTALLATION & SERVICE 5-26
Figure 5-23 Ignition Coil Test
Ignition Coil Electrical Troubleshooting (No code Indicated)
The following material covers the ignition coil mechanical or electrical problems
that do not indicate a Code 10. The ignition coil is ground side switched —
there is always voltage at the positive terminal to the ignition coil.
Symptom: No spark at the electrode (No code indicated)
Check: High tension wires and electrode
a) Inspect the high tension lead between the coil and the
electrode.
b) Inspect the ground lead between the second electrode and
the heater chassis.
c) Is the electrode gap adjusted correctly? (See page 5-13 for
Electrode Gap Detail)
Test Procedure:
a) Measure ignition coil resistance. Use a multimeter to measure
the resistance across the positive and negative terminals.
The resistance should be less than 1 ohm. If resistance is
“open circuit” or 0 ohms (short circuit) then replace the
ignition coil.
NOTE: Remove positive and negative wires from the coil when testing.