The ignition module on your GMC Jimmy controls the ignition spark sequence and firing of the ignition coils. However, the module's electronic components are very sensitive to heat. Prior to installation, cover the back of the module with silicone dielectric grease to protect it from overheating and subsequent failure. Then follow these steps to replace it.
Disconnect the negative battery cable.
Raise the front of your vehicle if you have a 2.2L engine, using a floor jack, and safely support it on 2 jack stands. Remove the air cleaner assembly if you have a 4.3L engine.
Disconnect the spark plug wires if you have a 2.2L engine. You have to work from underneath the vehicle and locate the ignition module towards the back of the engine. If necessary, make a note of the spark plug wires location to make sure you install them back correctly. If you have a 4.3L engine, you do not have to unplug the spark plug wires.
Unplug the electrical connector from the ignition module on 2.2L and 4.3L engines.
Remove the 3 mounting bolts from the ignition control module assembly on 2.2L engines, using a ratchet and socket, and remove the module from the engine compartment; on 4.3L, remove the mounting bolts and lift the module off the engine compartment.
Remove the coils from the ignition module assembly, if you have a 2.2L engine, using a ratchet and socket; then remove the module from the assembly plate.
Wipe the back of the ignition module with a clean piece of cloth and apply a light coat of silicone dielectric grease according to the manufacturer's recommendations. On 2.2L engines, install the module on the assembly plate. On 4.3L engines, install the module on its bracket, install the mounting screws and plug the electrical connector.
Install the ignition coils and mount the module assembly on the engine if you have the 2.2L engine. Plug the spark plug wires and electrical connector on the ignition module.
Install the air cleaner assembly if you have a 4.3L engine, and connect the black, negative battery cable. On 2.2L engines, lower the vehicle and connect the black, negative battery cable.
