Help, please. Need '78 wiring diagram
Thread Starter
Racer
Joined: Jul 2002
Posts: 285
Likes: 1
From: Edmond Oklahoma
Help, please. Need '78 wiring diagram
Specifically the dome lamp/courtesy lamp circuit. If somebody could point me to a webpage (couldn't find with a google search)or email one, I'd be grateful.
Thanks!
Thanks!
Melting Slicks
Joined: Aug 2001
Posts: 3,050
Likes: 124
From: Wichita KS
Re: Help, please. Need '78 wiring diagram (a454corvette)
a454corvette,
I don't know of a web site with wiring diagrams for a '78. However:
In the NCRS Electrical Wiring Diagrams book for 1973-82 Corvettes, there are two circuit diagrams. One is the common electrical circuit diagram which includes the dome light, and another is the diagram of the 1978 dome light delay circuit. A description of the dome light circuit follows. The dome delay circuit is more convoluted, I'll try to post a description if you need it.
Power to the dome light is supplied by circuit 140, an orange, 18 gauge, fused, battery feed wire.
Ground to the dome light is provided by circuit 156, a white, 18 gauge, switched controlled wire.
Power to the left and right hand courtesy lamps is also provided by circuit 140, an orange, in this case - 20 gauge wire.
Ground to the courtesy lamps is also provided by circuit 156, a white, in this case - 20 gauge wire.
Circuit 140 and 156 also power the spare tire illumination circuit.
Circuit 140 also supplies power to the clock, glove box, and cigar lighter.
ORANGE Wires Circuit 140. The diagram shows the orange (power) 18 gauge dome lamp wire connecting to the orange 18 gauge wire that runs to the spare tire. Both dome and tire circuits are connected to an orange 20 gauge that runs forward where it joins with the orange power wires (all circuit 140) that run to the clock, glove box, cigar lighter, and courtesy lamps. An orange, 14 gauge, circuit 140, wire provides power to this connection from the fuse box. The circuit 140 fuse is 20A.
WHITE Wires Circuit 156 Switched Ground. Switchs are at the left and right and doors and at the light switch. The diagram shows the white, 18 gauge dome lamp wire connected to the white, 18 gauge spare tire lamp wire. These are connected to a white (also circuit 156) 20 gauge wire that runs forward where it joins with the white, circuit 156 wires that run to the courtesy lamps. the left and right door jam switches and the headlamp switch.
The door jams provide ground to the door switchs.
Two wires connect to the right hand door switch, the white wire is circuit 156 that controls the dome/courtesy lamps, the light blue wire is to the anti-theft circuit 263.
Three wires connect to the left hand door switch, the tan wire is the key warning buzzer, circuit 159. White and light blue are the same as the right hand door.
The diagram shows the white wires from left and right hand door switchs joining together, and then a single white wire runs to connect to the other circuit 156 wires.
The headlamp switch ground is provided by Circuit 150, a black, 12 gauge, direct ground wire.
(When I say forward/back, I mean relative to the circuit diagram. Most of this looks like it is under the dash and by the fuse panel.) Hope this helps.
I don't know of a web site with wiring diagrams for a '78. However:
In the NCRS Electrical Wiring Diagrams book for 1973-82 Corvettes, there are two circuit diagrams. One is the common electrical circuit diagram which includes the dome light, and another is the diagram of the 1978 dome light delay circuit. A description of the dome light circuit follows. The dome delay circuit is more convoluted, I'll try to post a description if you need it.
Power to the dome light is supplied by circuit 140, an orange, 18 gauge, fused, battery feed wire.
Ground to the dome light is provided by circuit 156, a white, 18 gauge, switched controlled wire.
Power to the left and right hand courtesy lamps is also provided by circuit 140, an orange, in this case - 20 gauge wire.
Ground to the courtesy lamps is also provided by circuit 156, a white, in this case - 20 gauge wire.
Circuit 140 and 156 also power the spare tire illumination circuit.
Circuit 140 also supplies power to the clock, glove box, and cigar lighter.
ORANGE Wires Circuit 140. The diagram shows the orange (power) 18 gauge dome lamp wire connecting to the orange 18 gauge wire that runs to the spare tire. Both dome and tire circuits are connected to an orange 20 gauge that runs forward where it joins with the orange power wires (all circuit 140) that run to the clock, glove box, cigar lighter, and courtesy lamps. An orange, 14 gauge, circuit 140, wire provides power to this connection from the fuse box. The circuit 140 fuse is 20A.
WHITE Wires Circuit 156 Switched Ground. Switchs are at the left and right and doors and at the light switch. The diagram shows the white, 18 gauge dome lamp wire connected to the white, 18 gauge spare tire lamp wire. These are connected to a white (also circuit 156) 20 gauge wire that runs forward where it joins with the white, circuit 156 wires that run to the courtesy lamps. the left and right door jam switches and the headlamp switch.
The door jams provide ground to the door switchs.
Two wires connect to the right hand door switch, the white wire is circuit 156 that controls the dome/courtesy lamps, the light blue wire is to the anti-theft circuit 263.
Three wires connect to the left hand door switch, the tan wire is the key warning buzzer, circuit 159. White and light blue are the same as the right hand door.
The diagram shows the white wires from left and right hand door switchs joining together, and then a single white wire runs to connect to the other circuit 156 wires.
The headlamp switch ground is provided by Circuit 150, a black, 12 gauge, direct ground wire.
(When I say forward/back, I mean relative to the circuit diagram. Most of this looks like it is under the dash and by the fuse panel.) Hope this helps.
Drifting
Joined: Feb 2000
Posts: 1,607
Likes: 0
From: Clarksville,Tn,USA TN
Re: Help, please. Need '78 wiring diagram (mapman)
Here is a online electrical manual for a 78 corvette. Enjoy..The first link is the index the second the courtesy circuit. I also have a 78 if you have any other questions.
Neil in Tenn
http://www.corvetteforum.net/c3/tune...l/index6.shtml
http://www.corvetteforum.net/c3/tune.../index19.shtml
Neil in Tenn
http://www.corvetteforum.net/c3/tune...l/index6.shtml
http://www.corvetteforum.net/c3/tune.../index19.shtml
