What is pin 1 of the Ford C115 connector?

Pin 1 is power for the coils, key-on, fed by a 20a fuse.

Which C115 pins connect to the DLC (diagnostic) connector?

Pin 3 goes to DLC pin 10, pin 11 goes to DLC pin 2, and pin 22 goes to DLC pin 13.

Which C115 pins are grounds?

Pin 13 and pin 34 are grounds, and pin 42 is listed as 'ground?' (uncertain).

What does pin 36 of C115 do?

Pin 36 is a 20a fuse after the PCM relay, powering the O2 sensor heaters.

Which C115 pins are unused?

Pins 10, 23, 32, 35, 38, and 41 are shown with dashes (no function), and pin 28 is marked '-null-'.

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Ford C115 Connector Pinout - PCM/EEC 42-Pin Wiring Functions Diagram

C115 connector pinout chart listing 42 pin numbers with signal functions like power for coils, tachometer and DLC connector

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Connector pinout chart for the C115 connector listing all 42 pins and their electrical signal assignments and circuit functions.

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This document is a pin-by-pin legend for the Ford C115 connector, listing the function of each of its 42 pins. Powered circuits include pin 1 (power for coils, key-on 20a fuse), pin 8 (power hot at all times, 20a fuse), pin 9 (power from EEC relay), pin 25 (10a fuse hot on run), and pin 36 (20a fuse after PCM relay for O2 heaters). Diagnostic connections include DLC connector pins 10, 2, and 13 (connector pins 3, 11, and 22). Engine/transmission-related pins include tachometer, BOO switch (disables lockup converter), fuel pump relay monitor and signal, check engine light, VSS to GEM, OD off button and light, EVAP purge valve, coolant temp gauge, fuel tank pressure, signal return, reference voltage, MLPS, reverse lights, starter solenoid pre- and post-MLPS, oil pressure, message center fuel flow, 4x4 low range indicator, A/C shutoff relay signal and AC pressure switch monitor, park/neutral for GEM, and vapor management valve. Several pins (10, 23, 32, 35, 38, 41) are unused (dashed) and pin 28 is marked null; pins 13, 34, and 42 are grounds (42 marked with a question mark). Readers can use it to identify wiring functions when diagnosing or splicing at connector C115.

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Frequently asked questions

What is pin 1 of the Ford C115 connector?: Pin 1 is power for the coils, key-on, fed by a 20a fuse.
Which C115 pins connect to the DLC (diagnostic) connector?: Pin 3 goes to DLC pin 10, pin 11 goes to DLC pin 2, and pin 22 goes to DLC pin 13.
Which C115 pins are grounds?: Pin 13 and pin 34 are grounds, and pin 42 is listed as 'ground?' (uncertain).
What does pin 36 of C115 do?: Pin 36 is a 20a fuse after the PCM relay, powering the O2 sensor heaters.
Which C115 pins are unused?: Pins 10, 23, 32, 35, 38, and 41 are shown with dashes (no function), and pin 28 is marked '-null-'.