REGULATOR ASSEMBLY 2M8965 - Caterpillar

Illustration 1. Typical 24V starting circuit without a start relay.
Illustration 2. Typical 24V starting circuit with a start relay.For Illustration 1 circuit, add a 3T2171 Relay Assembly and a 9F3099 Switch (Start Relay). See Illustration 3.
Illustration 3. Typical 24V starting circuit with both the relay assembly and switch (start relay) added.For Illustration 2 circuit that already contains the 9F3099 Switch or equivalent, add only a 3T2171 Relay Assembly. See Illustration 3.
With the correct modification, when the engine starts, the alternator (R) terminal causes the 3T2171 Relay Assembly to pull in and inhibit the 9F3099 Switch. This prevents actuation of the starter.