Pin 4 on the Select Monitor harness (which Subaru also refers to on its wiring diagrams as the "Data Link Connector") is connected to pin 5 of the Cruise Control Module. Has anyone determined what that pin does? The wiring diagrams show only those two things interconnected.
I've started making the older-style Subaru radio harnesses with both illumination wires. A byproduct will be extra 9-pin harnesses, which I'm planning to offer to people who want to build a Select Monitor / DLC port interface. These harnesses will have only the 4 wires needed for the Select Monitor (Black, Red, Green, and Violet for Ground, +12V, TxD, and RxD, respectively). Price will be just a few bucks. If interested, please e-mail me (see my
harness for sale post).
If we discover that the cruise control pin is useful for anything, I can throw in an extra wire so people can access it.
Also, the USDM SVX wiring diagrams (both '92 and '96) show DLC pin 8 connecting to pin c15 on the ECU. The DLC harness in my '96 has no wire there. Is that wire present in earlier years? If so, has anyone figured out what that pin does?