78 Electrical Problem interior lights
Thread Starter
Burning Brakes
Joined: Oct 2010
Posts: 1,192
Likes: 7
From: Wentzville MO
78 Electrical Problem interior lights
I have replaced my interior in my 78 and had also removed and replaced the light switch and steering wheel. During the entire interior replacement the interior lights and horn didn't work. I replaced the light switch and they would turn on when turning the dimmer switch all the way to the left. When I installed the steering wheel I heard the horn beep once like a had shorted something with the screwdriver. All the interior lights came and stayed on. I shut the doors and the lights stay on. Checked the two door switches they seem fine and work as they should. I also noticed a light by the bottom of the rear license plate was on.
I removed the steering wheel, and interior lights continue to stay on. I don't know if horn worked before I removed the old steering wheel. I currently removed all the bulbs to keep from draining the battery. Dimmer light switch appears to be working as should. Where do I start to troubleshoot?
I removed the steering wheel, and interior lights continue to stay on. I don't know if horn worked before I removed the old steering wheel. I currently removed all the bulbs to keep from draining the battery. Dimmer light switch appears to be working as should. Where do I start to troubleshoot?
Melting Slicks
Joined: Oct 2006
Posts: 2,417
Likes: 336
From: Texas
some 78's had a delay timer for the interior lights, its in upper right hand dash ( usually a small orange box). it may have quit timing out. the spare tire light is part of the courtesy light system, its supposed to be on, if interior lights are on. i believe you can jumper the delay timer wiring. white to white to bypass it.??
http://www.corvetteforum.net/c3/tune.../index19.shtml
http://www.corvetteforum.net/c3/tune.../index19.shtml
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,851
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,851
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
The delay timer works under the dash by interrupting the ground.
You said you did all the interior.. is there a chance maybe one of the roof panels screws is in to the wires on the halo? I did see this happen once.
Willcox
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Safety Car
Joined: Sep 2005
Posts: 4,057
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From: Southeast, Tennessee
St. Jude Donor '09 thru '26
i believe you stated that you turned the headlight "dimmer" switch all the way to the left. that should turn all the interior courtesy lights on manually and keep them on. if you haven't rotated it back a bit to the right to get it off the "all on" position, all those lights will stay on. you shouldn't see any difference by disconnecting the harmonica coupling on the steering column as the courtesy lights aren't connected to or through anything in the column. perhaps i missed something, but that is what i got from your original post.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
(You are correct in that the courtesy lights don't go through the column but the tan from the ign key switch buzzer plugs in 1/64" away from the white courtesy light ground wire on the drivers door jamb switch !
All the wires on the door switch are looking for a ground but when the plunger is pushed in all wires must not be touching.)
Thread Starter
Burning Brakes
Joined: Oct 2010
Posts: 1,192
Likes: 7
From: Wentzville MO
Unplugged the. harmonica tonight and lights still stay on. The ign buzzer has been removed by previous bubba.
The top screws around the t top area haven't been installed yet so no screws grounding wires out. I also removed the kick panels and double checked the wires for damage, all appear ok.
The dimmer switch is turned all the way to the right which dims all the dash lights which work when switch is pulled out.
Where would the timer be located? I pulled the glove box and didn't see anything that looks like the picture from Willcox.
The top screws around the t top area haven't been installed yet so no screws grounding wires out. I also removed the kick panels and double checked the wires for damage, all appear ok.
The dimmer switch is turned all the way to the right which dims all the dash lights which work when switch is pulled out.
Where would the timer be located? I pulled the glove box and didn't see anything that looks like the picture from Willcox.
Last edited by donnie1956; Mar 18, 2011 at 09:54 PM. Reason: more info added
