The 1990 Engine Control Wiring Harness

[19Eclipse90]

B-29: Engine Coolant Temperature Gauge Unit

This is just a single spade connector. Out of three harnesses I have, this has been broken off of each one. It runs to number 4 in the diagram provided.

[19Eclipse90]

B-30: Engine Coolant Temperature Sensor (for ECU)

This runs to number 5 in the following diagram.

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B-31: Engine Coolant Temperature Switch (for A/C)

This is for number 6 in the diagram provided.

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B-32: Crank Angle and Top Dead Center Sensor (Cam Angle Sensor, CAS)

The 1990 CAS has a built in harness that tails back to this connector on the firewall. On later models, the harness connects directly to the sensor.

[19Eclipse90]

C-56: Oxygen Sensor Check Connector

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C-57: Control Wiring Harness and Body Wiring Harness Combination (1-pin, passenger side kick panel)

[19Eclipse90]

C-58: Control Wiring Harness and Body Wiring Harness Combination (16-pin, passenger side kick panel)

One of two interior connectors that will require modification if the 1990 harness is swapped into a 1991+ car or vice versa. A 1990 harness has a 16-pin connector and fills up every slot. The later models switched to a 18-pin connector (see pin-out here).

The second and third picture show a 1991+ connector transferred onto a 1990 vehicle which was undergoing a turbo swap with a '91 engine, manual harness, and ECU. Note, first, that this is the female end. Secondly, that the two end pin locations are empty; the pins/wires were swapped directly to the '91 connector to the exact location from which they were located on the '90 harness.

[19Eclipse90]

C-59: Control Wiring Harness and Body Wiring Harness Combination (6-pin, passenger side kick panel)

See the C-59 pin-out here. Note that pin 6, the black with green, switches to black with white on the mating connector in the body harness.

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C-63: MPI Control Relay

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C-64: MPI Control Unit (ECU, small connector)

Use this to relate wire colors to ECU function: http://www.vfaq.com/mods/ecu-harness-1G.html.

ERROR: I will get to fixing this eventually, but the "green" wire on pin 105 is actually ORANGE.

[19Eclipse90]

C-65: MPI Control Unit (ECU, medium connector)

Use this to relate wire colors to ECU function: http://www.vfaq.com/mods/ecu-harness-1G.html.

[19Eclipse90]

**C-66: MPI Control Unit (ECU, large connector)

Note the wire colors of pin 6 (green) and 14 (green w/ white). The green with white stripe wire in all turbo applications runs to pin 1 of the air flow sensor (A-36); this pin slot will be empty in non-turbo models. The green is for the idle, or closed throttle, position switch, which is pin 4 of the throttle position sensor connector on the 1990 (B-02 & B-05) and its own single wire connector on 1991+ models. Information on how to swap 1G ECU pins can be found here: How to remove/replace pins in harness connectors.

Use this to relate wire colors to ECU function: 1G ECU Pinouts.

[19Eclipse90]

C-67: Control Wiring Harness and Body Wiring Harness Combination (under center console)

When swapping this harness into a 1991-1994 1G, this connector will not match up. The 1990 car uses an 8-pin, 7-wire connector. Later manual transmission 1G cars have a 14-pin connector (see manual connector pin-out and a visual) where the later automatic 1Gs have an 18-pin connector (see auto connector pin-out).

Also see these for a visual on where this connector is accessed inside the vehicle:
Cant find were this clip goes. Help!
Harness swap difficulties.

The second picture shows a '91+ manual connector that was transferred into a 1990 vehicle which was undergoing a turbo conversion with a '91 engine, harness, and ECU. The third picture is the 1991 connector on the engine harness.