Question: I bought my Envoy new in March 2003 and have driven it 113,000 miles with a few small problems but nothing major. The truck, however, is on its third ignition switch. Normally I drive to work and run errands, and do not think I am starting the SUV excessively to wear out the part. My dealer says that particular ignition switch is widely used in the GM product lineup and blames GM for underdesigning the part. Has this part failure been a problem for GM for many years as my dealer claims?

Answer: It looks like that design ignition switch has been used in various GM-built pickups and SUVs beginning in 1998. In general, I recommend Original Equipment Manufacturer parts as opposed to aftermarket brands. OEM parts are typically higher quality, designed with narrower tolerances, and there is less chance of getting the wrong part or one that "almost" fits. However, there are always exceptions to the rule. If the service personnel at the GMC dealership you're working with have noted replacement of this particular ignition switch as being a common event, that particular ignition switch may very well be a weak link. That being the case--and if it fails again--replace it with an aftermarket ignition switch from a local parts distributor. One part may not have the defective element that is failing in the other. GM TSB #04-06-03-002 pertains to the ignition switch in a 2003 Envoy and other vehicles, but does not deal with a defective switch--rather the tendency of the switch to be installed incorrectly. The ignition switch is mounted to the lock cylinder assembly inside the steering column. During installation of a new switch, a gear protruding from the switch must be "indexed" (lined up) properly with the lock cylinder assembly. If it's off a tooth in one direction there may be a power drain on the battery while the ignition is in the OFF position. Off a tooth in the other direction may cause an intermittent no-start condition.

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