Ignition Relay Circuit
- Perform On-Board Diagnostic (OBD) System Check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in TESTS W/CODES - 5.7L article. After performing OBD system check, go to next step.
- Turn ignition off. Remove IGN relay from underhood electrical center. Using test light connected to ground, probe IGN relay connector battery positive feed circuit. See WIRING DIAGRAMS - 5.7L article. If test light illuminates, go to next step. If test light does not illuminate, go to step 8).
- Turn ignition on with engine off. Using test light connected to ground, probe IGN relay connector ignition feed circuit. See WIRING DIAGRAMS - 5.7L article. If test light illuminates, go to next step. If test light does not illuminate, go to step 9).
- Turn ignition off. Using DVOM connected to ground, check resistance of IGN relay connector ground circuit. See WIRING DIAGRAMS - 5.7L article. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, go to step 10).
- Turn ignition off. Connect a fused jumper wire between IGN relay battery positive feed circuit and IGN relay load circuit. See WIRING DIAGRAMS
- 5.7L article. Using test light connected to ground, probe terminals of the following fuses located in underhood electrical center No. 2.
- A/C ("Y" Body)
- A/C CRUISE ("F" Body)
- AIR PUMP ("Y" Body)
- ENG CTRL ("F" Body)
- ENG IGN1 ("Y" Body)
- ENG SEN ("F" Body)
- INJR1
- INJR2
- THROT CONT ("Y" Body)
If test light illuminates on all fuses, go to next step. If test light does not illuminate, go to step 11 .
- Check for poor terminal connection at IGN relay connector. Repair or replace as necessary. If terminal connection is okay, go to next step.
- Replace IGN relay.
- Repair open in IGN relay battery voltage feed circuit.
- Repair IGN relay ignition feed circuit.
- Repair open in IGN relay ground circuit.
- Repair IGN relay load circuit.