One problem related to defogger heater has been reported for the 1998 GMC Safari. The most recently reported issues are listed below.
Brakes werent working well, then noticed heater didnt work, speed odemter didnt work. Took to GMC repair shop, was told GMC as a problem with fuel injectors leaking in to dash of vehicles. Large repair bill. Needs new wiring harness, fuel injectors, metering body not sure what else til they fix dash. Recommended not to drive more damage will occor or will short out other things. Or cause a fire. GMC wont back up their vehicle. Debbie lull.