Where is the power wire on a 94 Suburban?

Delco-Remy Alternator Problem 94 amp?

• Had the above alternator installed on a Perkins 4-108 which burnt out after 10 years, can't complain! This unit replaced a 50 amp to give me more charging power. I have three other spares of different amperages and are all identical and all Delco-Remy. When I pulled the burnt one out there was a green wire coming out of the back of the unit which is attatched to one of the windings on the block inside and connected to a green wire on the harness. I replaced the unit with a spare which neither of them have this green wire coming out of the back, now I have no Tach reading? The strange thing is that one of the three spares was the one replaced by the 94 amp and none have this wire coming out of the back. Each unit has the normal pos/neg terminals and the two sensor connectors but none have this strange wire? Anyone help??

• Answer:

  Sounds like they used a outboard tach that is driven off the alternator. On an outboard they use use 1/2 of a a/c pulse to read rpm. Sounds like they did the same here. Since you don't have an ignition system, other than a cable drive tach, they are using a a/c pulse. Take your old alt and new to an rebuild shop, they should be able to add it.