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Circuit Description

WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

The ignition relay is normally an open relay. The relay armature is held in the open position by spring tension. When the ignition switch is turned to the Run or Start position, current will flow through the relay coil. A wire connected to the other end of the relay coil completes the path to ground. The electromagnetic field created by the relay coil overcomes the spring tension and moves the armature, allowing the relay contacts to close. The closed relay contacts allow current to flow from the battery to the following fuses:

When the ignition switch is turned to the OFF position, the electromagnetic field collapses. This action allows the spring tension to move the armature away from the relay contacts, which interrupts current flow to the fuses.

If the ignition relay fails to close, the engine will crank but will not run. The class 2 communications will be available with the use of a scan tool.

The ignition relay table assumes that the vehicle battery is fully charged. Refer to Battery Inspection/Test in Engine Electrical.

Ignition Relay Diagnosis

Step Action Yes No
Schematic Reference:  Ground Distribution Schematics  and  Power Distribution Schematics  in Wiring Systems, and  Engine Controls Schematics 
Connector End View Reference:  Engine Controls Connector End Views  or  Powertrain Control Module (PCM) Connector End Views 
1 Did you perform the Diagnostic System Check-Engine Controls? Go to Step 2  Go to Diagnostic System Check - Engine Controls
2
  1. Turn ON the ignition, with the engine OFF.
  2. Remove the underhood junction block cover.
  3. Probe the following fuses with a test lamp that is connected to a good ground.
Does the test lamp illuminate on at least one test point of each fuse?		 Go to Step 3  Go to Step 11 
3
  1. Turn OFF the ignition.
  2. Probe both test points of the Fuel INJ fuse with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors and Troubleshooting with a Test Lamp in Wiring Systems.
Does the test lamp illuminate on either test point of the fuse?		 Go to Step 4  Go to Step 43 
4
  1. Turn OFF the ignition.
  2. Remove the ignition relay from the underhood junction block with the J 43244  Relay Puller Pliers and Relay Replacement (Attached to Wire Harness) or Relay Replacement (Within an Electrical Center) in Wiring Systems.
  3. Probe both test points of the 10-amp IGN 1 fuse in the underhood junction block with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors and Troubleshooting with a Test Lamp in Wiring Systems.
Does the test lamp illuminate on any of the fuse test points?		 Go to Step 7  Go to Step 5 
5 Test the ignition relay load circuit bus bar of the underhood junction block between the ignition relay and the fuses to the circuit components for a short to battery positive voltage. Refer to Circuit Testing in Wiring Systems.
Did you find and correct the condition?		 Go to Step 42  Go to Step 6 
6
  1. Turn OFF the ignition.
  2. Remove the following fuses from the underhood junction block:
    • The Eng Controls fuse
    • The Fuel INJ fuse
    • The Elec Eng fuse
    • The O2 Sensors fuse
    • The Trans Sol fuse
    • The ABS fuse
    • The AWD fuse
  3. Probe all these fuse terminals in the underhood junction block with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors and Troubleshooting with a Test Lamp in Wiring Systems.
Does the test lamp illuminate at any of the fuse terminals?		 Go to Diagnostic System Check - Engine Electrical in Engine Electrical Go to Step 39 
7
  1. Turn OFF the ignition.
  2. Disconnect the ignition switch electrical connector.
  3. Connect a 20-amp fused jumper wire from the battery positive voltage wire terminal at the ignition switch harness connector to the battery positive voltage terminal at the ignition switch. Refer to Using Fused Jumper Wires in Wiring Systems.
  4. Probe the ignition 1 voltage terminal of the ignition switch with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors and Troubleshooting with a Test Lamp in Wiring Systems.
Does the test lamp illuminate?		 Go to Step 40  Go to Step 8 
8
  1. Turn OFF the ignition.
  2. Disconnect the negative battery cable at the battery. Refer to Battery Negative Cable Disconnect/Connect Procedure (LA1) or Battery Negative Cable Disconnect/Connect Procedure (LY7) in Engine Electrical.
  3. Disconnect the console junction block electrical connector that contains the ignition 1 voltage circuit from the ignition switch.
  4. Connect the negative battery cable to the battery.
  5. Probe the ignition 1 voltage circuit between the ignition switch and the console junction block at the console junction block electrical connector with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors and Troubleshooting with a Test Lamp in Wiring Systems
Does the test lamp illuminate?		 Go to Step 35  Go to Step 9 
9
  1. Turn OFF the ignition.
  2. Disconnect the negative battery cable at the battery. Refer to Battery Negative Cable Disconnect/Connect Procedure (LA1) or Battery Negative Cable Disconnect/Connect Procedure (LY7) in Engine Electrical.
  3. Disconnect the underhood junction block electrical connector that contains the ignition 1 voltage circuit for the ignition relay.
  4. Connect the negative battery cable to the battery.
  5. Probe the ignition 1 voltage circuit of the ignition relay at the underhood junction block electrical connector with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors and Troubleshooting with a Test Lamp in Wiring Systems
Does the test lamp illuminate?		 Go to Step 38  Go to Step 10 
10 Test the ignition 1 voltage bus bar circuit for the ignition relay in the console junction block for a short to battery positive voltage. Refer to Circuit Testing in Wiring Systems.
Did you find a condition?		 Go to Step 41  Go to Step 42 
11
  1. Turn OFF the ignition.
  2. Probe both test points of the 20-amp IGN 3 fuse in the underhood junction block with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors and Troubleshooting with a Test Lamp in Wiring Systems.
Does the test lamp illuminate on both test points of the fuse?		 Go to Step 19  Go to Step 12 
12 Does the test lamp illuminate on one test point of the 20-amp IGN 3 fuse? Go to Step 13  Go to Step 28 
13 Test the battery positive voltage circuit between the underhood junction block and the ignition switch for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 43  Go to Step 14 
14 Test the ignition 1 voltage circuit between the ignition switch and the console junction block for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 43  Go to Step 15 
15 Test the ignition 1 voltage circuit between the console junction block and the underhood junction block for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 43  Go to Step 16 
16 Test the ignition 1 voltage bus bar circuit of the console junction block between the ignition switch and the underhood junction block for a short to ground. Refer to Circuit Testing in Wiring Systems.
Did you find a condition?		 Go to Step 41  Go to Step 17 
17 Test the ignition 1 voltage bus bar circuit of the underhood junction block up to the 10-amp IGN 1 fuse for a short to ground. Refer to Circuit Testing in Wiring Systems.
Did you find a condition?		 Go to Step 42  Go to Step 18 
18 Test the battery positive voltage bus bar circuit of the underhood junction block from the 20-amp IGN 3 fuse for a short to ground. Refer to Circuit Testing in Wiring Systems.
Did you find a condition?		 Go to Step 42  Go to Step 40 
19
  1. Turn ON the ignition, with the engine OFF.
  2. Probe both test points of the 10-amp IGN 1 fuse in the underhood junction block with a test lamp that is connected to a good ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Does the test lamp illuminate on both test points of the fuse?		 Go to Step 29  Go to Step 20 
20 Does the test lamp illuminate on one test point of the 10-amp IGN 1 fuse? Go to Step 27  Go to Step 21 
21
  1. Turn ON the ignition, with the engine OFF.
  2. Probe the ignition 1 voltage circuit at the ignition switch electrical connector with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors and Troubleshooting with a Test Lamp in Wiring Systems.
Does the test lamp illuminate?		 Go to Step 24  Go to Step 22 
22 Test the battery positive voltage circuit between the underhood junction block and the ignition switch for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct a condition?		 Go to Step 43  Go to Step 23 
23
  1. Turn OFF the ignition.
  2. Probe the mounting stud for the battery positive cable at the underhood junction block with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors and Troubleshooting with a Test Lamp in Wiring Systems.
Does the test lamp illuminate?		 Go to Step 40  Go to Diagnostic System Check - Engine Electrical in Engine Electrical
24
  1. Turn ON the ignition, with the engine OFF.
  2. Probe the ignition 1 voltage circuit for the ignition relay at the console junction block electrical connector that leads from the ignition switch with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors and Troubleshooting with a Test Lamp in Wiring Systems.
Does the test lamp illuminate?		 Go to Step 25  Go to Step 36 
25
  1. Turn ON the ignition, with the engine OFF.
  2. Probe the ignition 1 voltage circuit for the ignition relay at the console junction block electrical connector that leads to the underhood junction block with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors and Troubleshooting with a Test Lamp in Wiring Systems.
Does the test lamp illuminate?		 Go to Step 26  Go to Step 41 
26
  1. Turn OFF the ignition.
  2. Disconnect the negative battery cable at the battery. Refer to Battery Negative Cable Disconnect/Connect Procedure (LA1) or Battery Negative Cable Disconnect/Connect Procedure (LY7) in Engine Electrical.
  3. Disconnect the underhood junction block electrical connector that contains the ignition 1 voltage circuit for the ignition relay.
  4. Connect the negative battery cable at the battery.
  5. Turn ON the ignition, with the engine OFF.
  6. Probe the ignition 1 voltage circuit at the underhood junction block electrical connector with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors and Troubleshooting with a Test Lamp in Wiring Systems.
Does the test lamp illuminate?		 Go to Step 42  Go to Step 37 
27 Test the ignition 1 voltage bus bar circuit of the underhood junction block between the 10-amp IGN 1 fuse and the ignition relay for a short to ground. Refer to Circuit Testing in Wiring Systems.
Did you find a condition?		 Go to Step 42  Go to Step 39 
28
  1. Turn OFF the ignition.
  2. Probe the mounting stud for the battery positive cable at the underhood junction block with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors and Troubleshooting with a Test Lamp in Wiring Systems.
Does the test lamp illuminate?		 Go to Step 42  Go to Diagnostic System Check - Engine Electrical in Engine Electrical
29
  1. Turn OFF the ignition.
  2. Remove the ignition relay with the J 43244  from the underhood junction block.
  3. Probe the battery positive voltage circuit of the ignition relay at the underhood junction block with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors and Troubleshooting with a Test Lamp in Wiring Systems.
Does the test lamp illuminate?		 Go to Step 30  Go to Step 42 
30
  1. Turn ON the ignition, with the engine OFF.
  2. Probe the ignition 1 voltage circuit of the ignition relay at the underhood junction block with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors and Troubleshooting with a Test Lamp in Wiring Systems.
Does the test lamp illuminate?		 Go to Step 31  Go to Step 42 
31
  1. Turn ON the ignition, with the engine OFF.
  2. Probe the coil ground circuit of the ignition relay at the underhood junction block with a test lamp that is connected to battery voltage. Refer to Probing Electrical Connectors and Troubleshooting with a Test Lamp in Wiring Systems.
Does the test lamp illuminate?		 Go to Step 33  Go to Step 32 
32
  1. Turn OFF the ignition.
  2. Disconnect the negative battery cable at the battery. Refer to Battery Negative Cable Disconnect/Connect Procedure (LA1) or Battery Negative Cable Disconnect/Connect Procedure (LY7) in Engine Electrical.
  3. Disconnect the underhood junction block electrical connectors.
  4. Test the coil ground circuit wire of the ignition relay at the underhood junction block electrical connector for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 43  Go to Step 42 
33
  1. Turn OFF the ignition.
  2. Jumper the ignition relay battery positive voltage circuit and the ignition relay load circuit together at the underhood junction block with a 20-amp fused jumper wire. Refer to Using Fused Jumper Wires in Wiring Systems.
  3. Probe the following fuses with a test lamp that is connected to a good ground:
Does the test lamp illuminate on at least one test point of each fuse?		 Go to Step 34  Go to Step 42 
34 Test for an intermittent and for a poor connection at the underhood junction block, ignition relay connector location. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Did you find a condition?		 Go to Step 42  Go to Step 39 
35 Repair the short to battery positive voltage in the ignition 1 voltage circuit between the ignition switch and the console junction block. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 Go to Step 43  -
36 Repair the high resistance or an open in the ignition 1 voltage circuit between the console junction block and the ignition switch. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 Go to Step 43  -
37 Repair the high resistance or an open in the ignition 1 voltage circuit between the console junction block and the underhood junction block. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 Go to Step 43  -
38 Repair the short to battery positive voltage in the ignition 1 voltage circuit between the console junction block and the underhood junction block electrical connector. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 Go to Step 43  -
39 Replace the ignition relay. Refer to Circuit Protection - Fusible Links in Wiring Systems.
Did you complete the replacement?		 Go to Step 43  -
40 Replace the ignition switch. Refer to Ignition Switch Replacement in Steering Wheel and Column.
Did you complete the replacement?		 Go to Step 43  -
41 Replace the console junction block. Refer to Console Electrical Center or Junction Block Replacement in Wiring Systems.
Did you complete the replacement?		 Go to Step 43  -
42 Replace the underhood junction center. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Did you complete the replacement?		 Go to Step 43  -
43
  1. Replace any open fuses.
  2. Turn OFF the ignition for 30 seconds.
  3. Attempt to start the engine.
Does the engine start and run?		 Go to Step 44  Go to Engine Cranks but Does Not Run 
44
  1. Clear the DTCs with a scan tool.
  2. Operate the vehicle for 5 minutes.
Does a DTC set during this ignition cycle?		 Go to Diagnostic Trouble Code (DTC) List System OK
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