[chevybuilder18]

Originally Posted by VetteVet

Well I pointed this out in the no. 8 post but I'll go over it again.

The L wire is the field exciter wire that goes to the regulator and turns on the alternator field to start the alternator charging sequence. It comes from a Key on voltage source, and must have a resistor inline to protect the diodes in the alternator, and to prevent voltage feed back to the ignition system to allow the engine to shut down when the key is shut off. This wire originates at the ignition switch and is usually run from the firewall block to the external voltage regulator on the stock truck systems until 73 or 74. It is a 16 gauge brown wire and can be used on the internal voltage regulated alternators in the SI series if it is connected to the no. 1 terminal on the alternator. When converting to the CS series alternators this wire can be run to the L terminal and must have at least a 35 ohm 3 watt resistor inline to the L terminal.

The large wire in the plug is the red sensing wire that tells the voltage regulator what the voltage is on the system. It should be connected at a junction of the battery, the alternator, and the rest of the circuits in the system. When the system voltage drops below charging output voltage the regulator will increase field current strength and allow more output from the alternator and when voltage increases too much then the regulator senses the voltage on the S wire and drops field voltage to prevent overcharging the battery and the system circuits.

Thanks vettevet, i now know how to do that now but it took awhile to get the nerves to be sure what i was doing. got everything hooked up. sorry its been the 8th time. just intimadated, alot of complicated stuff, but SI series alternator had this same connection so i thought examining the Older system, would help me hook my new one up. if i didnt hook it up to existing alternator wires like suggested, id probably still have a feed back and the engine wouldnt shut down. anyways i got the serpentine belt drive on, and the alternator rocks