This sounds like a passlock security system problem. First, make sure your battery is fully charged and that your alternator is properly maintaining the batterys' charge. If you start the engine and turn on the lights -- at night-- notice how bright they are. Then shut the engine off. If the lights go a little dimmer then your alternator is probably charging the battery properly. This is important-- why, you may ask? Well, if your battery is low it can cause the passlock system to act up and eventualy fail. The passlock system is a factory security system that works as follows: When you turn the key, your ignition switch activates the fuel pump and the passlock system. When the engine is cranked there is a specific resistance that is sent back to your passlock module. This resistance is matched to the resistance in a resistor located inside the passlock module. If this resistance is matched, the fuel pump is allowed to continue to deliver fuel to the engine. If not, your engine will start. If the battery is low, it can damage the resistor inside of your passlock module, rendering it somewhat useless. The passlock module resistor is sometimes inside of the ignition switch or in the module itself. If you are not a mechanic you should take the blazer to a dealer or to someone who understands the PASSLOCK system on your Blazer.
Tuesday, December 18th, 2007 AT 9:17 PM