1990 chevy truck s terminal location on alternator

One such system is GMвЂ™s regulated voltage control (RVC) system. Several more recent vehicles use a variety of methods to control the alternatorвЂ™s output more precisely, with an eye toward improved fuel economy. WeвЂ™ve grown accustomed to testing these conventional charging systems, and expect to see a certain amperage output and voltage level from the alternator at a specific engine rpm, with a large number of electrical loads applied. The alternator continues to pump out at least some current all of the time and the electrical system voltage is always maintained within a specified, narrow range. Once the battery has been adequately charged and the rest of the vehicleвЂ™s various systems are receiving enough current to operate properly, the alternator should be able to take a break, thus reducing the load on the engine, cutting wear and tear on the alternator and its drive system and improving fuel economy.Д«ut thatвЂ™s not what happens on many of the vehicles weвЂ™ve been seeing on the road over the years. Vehicles need a battery and a starter motor to get the engine started, and an alternator to provide current to the vehicleвЂ™s electrical system while the engine is running. One system that has received attention from several vehicle manufacturers in their attempts to improve fuel economy is the charging system. I believe thereвЂ™s an alternator problem, but IвЂ™m looking for a method to confirm this. When I started the engine, the F terminal PID went from 0% to 97% on the scanner. I unplugged the two-wire connector at the back of the alternator and probed the F terminal with a test light connected to B+. Scanning the PCM, I found that DTC P0622 was stored as a history code. The alternator charging rate was 13.85V at the end of the 10-minute idle period. I let the engine idle for 10 minutes and the warning light did not come on for me. The customerвЂ™s complaint was that at times the вЂњService Charging SystemвЂќ message on the dash was coming on at idle. A 2007 Chevy Silverado came into the shop recently.

1990 chevy truck s terminal location on alternator