GM Astro/Safari 1985-1996 Repair Guide

Ignition Module

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REMOVAL & INSTALLATION

The ignition module on the 2.5L and non-HVS 4.3L engine is located inside the distributor; it may be replaced without removing the distributor from the engine. The ignition control module (ICM) on 1995 and later VIN W 4.3L engines is just an electronic switch and does no controlling of the ignition system. It is attached to the ignition coil bracket.

1985-94 (non-HVS) Engines

See Figures 1, 2, 3 and 4



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Fig. Fig. 1: Module and pick-up coil for EST distributor



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Fig. Fig. 2: The module easily unbolts without disassembling the distributor on EST equipped engines



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Fig. Fig. 3: Unplug the internal connections before trying to remove the module



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Fig. Fig. 4: Heat sink grease must be applied when installing the module or it may fail due to overheating

  1. Disconnect the negative battery terminal and remove the console cover.
  2.  
  3. Remove the distributor cap and the rotor.
  4.  
  5. If the flange, of the distributor shaft is positioned above the module, place a socket on the crankshaft pulley bolt and rotate the crankshaft (turning the distributor shaft) to provide clearance to the ignition module.
  6.  
  7. Remove the ignition module-to-distributor bolts, lift the module and disconnect the electrical connectors from it.
  8.  
  9. If the module is suspected as being defective, take it to a module testing machine and have it tested.
  10.  

When replacing the module, be sure to coat the module-to-distributor surface with silicone lubricant (dielectric compound) that will provide heat dissipation.

To install:
  1. Apply silicone heat sink compound to the module mounting area of the distributor. Install the rotor, the distributor cap and connect the negative battery cable.
  2.  

1995-96 (HVS) Engines

  1. Disconnect the negative battery terminal and remove the console cover inside the vehicle.
  2.  
  3. Disconnect the engine control switch and tachometer terminals from the ignition coil and module.
  4.  
  5. Disconnect the ignition coil-to-distributor lead wire from the coil.
  6.  
  7. Remove the coil bracket/module assembly-to-engine bracket nuts and lift the assembly from the engine.
  8.  
  9. If necessary to remove the module from the bracket, perform the following procedures:
    1. Using a drill, drill out the module-to-bracket rivets.
    2.  
    3. Using a center punch, drive the rivets from the module-to-bracket assembly.
    4.  
    5. Remove the module from the coil bracket.
    6.  

  10.  

To install:
  1. Install the module on the bracket with two screws, position the coil on the engine and torque the nuts to 20 ft. lbs. (27 Nm).
  2.  
  3. Connect the coil connectors and negative battery cable. Install the console cover.
  4.  

 
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