Wiring for headlight 87 to 90
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1st Gear
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Wiring for headlight 87 to 90
How do I know what wire from a 1990 Corvette harness hooks up to the headlight motor? My Corvette is an 87 and there are more wires on the 1990 harness for the headlights.
Please and thank you for any help.
Please and thank you for any help.
Melting Slicks
Joined: Nov 2016
Posts: 2,256
Likes: 3,082
From: So Cal
2023 C4 of the Year Finalist - Unmodified
The 90 should have a 2-wire and a 3-wire connector. The 2-wire is for the motor, the 3-wire is for the headlight bulb.
The 87 should have (2) 3-wire connectors. One is for the motor, the other is for the headlight bulb.
Headlight bulb wire colors: Black = Ground, Lt Green = High Beam, Tan = Low beam. Same colors for both years. (Actually same colors for all years of C4 and about 6 decades of GM vehicles.)
> The 87 door motor has 3 wires. The 84-87 door motor circuit has 3 relays on the front of the LF wheel housing. There are limit switches in the motors themselves. When the travel reaches its stop the armature moves and opens the limit switch, stopping the current flow.
> The 88-96 door motor has 2 wires. The 88-96 circuit uses a solid state module to control the motors. When the travel reaches its stop, the current increases and the module turns off the power to the motor.
You can not mix components of the two systems on the same car. You can change both motors, the module and change some wiring to the later system. But you can't pop a 90 motor assembly into a 1987 with no other changes.
The 87 should have (2) 3-wire connectors. One is for the motor, the other is for the headlight bulb.
Headlight bulb wire colors: Black = Ground, Lt Green = High Beam, Tan = Low beam. Same colors for both years. (Actually same colors for all years of C4 and about 6 decades of GM vehicles.)
> The 87 door motor has 3 wires. The 84-87 door motor circuit has 3 relays on the front of the LF wheel housing. There are limit switches in the motors themselves. When the travel reaches its stop the armature moves and opens the limit switch, stopping the current flow.
> The 88-96 door motor has 2 wires. The 88-96 circuit uses a solid state module to control the motors. When the travel reaches its stop, the current increases and the module turns off the power to the motor.
You can not mix components of the two systems on the same car. You can change both motors, the module and change some wiring to the later system. But you can't pop a 90 motor assembly into a 1987 with no other changes.
