Primary Checks
1. Install an ammeter at the controller/relay terminal stud (glow plug side).
2. Connect the Tech 1. Using the Tech 1’s “Glow Plug Output Tests,” command the glow plugs “ON.”
3. Move the ignition switch to the RUN position and measure the amperage of each bank of the glow plugs.
• If both banks have a minimum of 55 amperes current flow, the system is working properly.
• If either bank has less than 55 amperes current flow, go to step 4.
• If both banks have a zero ampere current flow, perform the Secondary Checks as described in the “6.5L V8 Turbo Diesel” coursebook (#16015.12-2).
4. Install an ammeter in series with one glow plug wire. Move the ignition switch to RUN and measure the amperage of the glow plug.
• If the glow plug has a current flow of 14 amperes, it is working properly.
• If the glow plug has a current flow less than 14 amperes, go to step 5.
5. Check the continuity of the glow plug wiring harness from the relay terminal stud to the glow plug terminal.
• If the wiring harness has continuity, go to step 6.
• If the wiring harness has no continuity, repair it and check system operation.
6. Replace the glow plug and follow steps 4 and 5 for other glow plugs. Use an AC-type 9G glow plug.
7. When all glow plugs have 14 amperes of current flow, end the diagnosis.
