Tail and dash lights out when lights on
Thread Starter
Instructor
Joined: Apr 2016
Posts: 141
Likes: 11
From: KC, MO
Tail and dash lights out when lights on
Hoping someone who knows C3 wiring can help. On my 76 L48 Auto, when I turn on my lights, the tail lights and the dash lights don't come on. The head lights and rest of the car get power though. It is something that has been a problem for awhile, as sometimes they will work and sometimes not. Lately, it has been more of a not working situation. The brake lights work when I touch them. Seems like a specific circuit with those two things out (they seem to work hand-and-hand). I was thinking a bad ground, but anyone have the same problem or an idea as to where to start?
Burning Brakes
Joined: Mar 2013
Posts: 750
Likes: 180
From: Springfield Missouri
I just looked at the wiring diagram I have for my 76 and both of those circuits are fused. The fuse box is a major PITA to access and the glass fuses break easily. I would suspect that the fuses are either blown or not making good contact. If the fuses check good then it's probably the light switch. Do make sure all grounds are good solid grounds as that is a major problem on all vehicles and especially those that have any age. Good luck with your problem.
Thread Starter
Instructor
Joined: Apr 2016
Posts: 141
Likes: 11
From: KC, MO
I just looked at the wiring diagram I have for my 76 and both of those circuits are fused. The fuse box is a major PITA to access and the glass fuses break easily. I would suspect that the fuses are either blown or not making good contact. If the fuses check good then it's probably the light switch. Do make sure all grounds are good solid grounds as that is a major problem on all vehicles and especially those that have any age. Good luck with your problem.
The no fuses are blown. I suppose it could be a bad connection. With them on the same circuit, the fuse is a likely issue. Which fuse is it? I am curious about your light switch comment as well, any thoughts as to how I would check that? Finally, does anyone have an easy guide or picture that shows all of the c3’s ground locations. That certainly would be really helpful.
Burning Brakes
Joined: Mar 2013
Posts: 750
Likes: 180
From: Springfield Missouri
I replaced the switch in mine because it was faulty. The rheostat or it's contacts that controls the brightness of the dash lights is generally the problem.
This spring when I tear mine down to replace a leaking heater core I plan on replacing the fuse box with one that has the right amount of circuits and blade fuses. It will most likely come from the junkyard as I've been wiring on stuff since the 60's.
There's a member on this forum, papawana I believe who will send you a wiring diagram for you car. You can also get them from Willcox, a vendor on this forum or you can find them on eBay such as this.
https://www.ebay.com/itm/CORVETTE-19...oAAOSwm6JaU5vV
This spring when I tear mine down to replace a leaking heater core I plan on replacing the fuse box with one that has the right amount of circuits and blade fuses. It will most likely come from the junkyard as I've been wiring on stuff since the 60's.
There's a member on this forum, papawana I believe who will send you a wiring diagram for you car. You can also get them from Willcox, a vendor on this forum or you can find them on eBay such as this.
https://www.ebay.com/itm/CORVETTE-19...oAAOSwm6JaU5vV
Thread Starter
Instructor
Joined: Apr 2016
Posts: 141
Likes: 11
From: KC, MO
I replaced the switch in mine because it was faulty. The rheostat or it's contacts that controls the brightness of the dash lights is generally the problem.
This spring when I tear mine down to replace a leaking heater core I plan on replacing the fuse box with one that has the right amount of circuits and blade fuses. It will most likely come from the junkyard as I've been wiring on stuff since the 60's.
There's a member on this forum, papawana I believe who will send you a wiring diagram for you car. You can also get them from Willcox, a vendor on this forum or you can find them on eBay such as this.
https://www.ebay.com/itm/CORVETTE-19...oAAOSwm6JaU5vV
This spring when I tear mine down to replace a leaking heater core I plan on replacing the fuse box with one that has the right amount of circuits and blade fuses. It will most likely come from the junkyard as I've been wiring on stuff since the 60's.
There's a member on this forum, papawana I believe who will send you a wiring diagram for you car. You can also get them from Willcox, a vendor on this forum or you can find them on eBay such as this.
https://www.ebay.com/itm/CORVETTE-19...oAAOSwm6JaU5vV
Thanks, that’s really helpful. Probably a dumb question but where is the switch? I guess I didn’t even know there was a dimmer. When my lights do work in the dash they are really dim.
Burning Brakes
Joined: Mar 2013
Posts: 750
Likes: 180
From: Springfield Missouri
The rheostat is located in the front of the light switch and is controlled by the rotation of the ****. IIRC, since I don't drive my Vette much at night, rotating the **** clockwise will make the lights brighter and full rotation will also turn on the interior lights as well. Are you aware that the headlight dimmer switch is located at the upper left of the toe board?
Thread Starter
Instructor
Joined: Apr 2016
Posts: 141
Likes: 11
From: KC, MO
The rheostat is located in the front of the light switch and is controlled by the rotation of the ****. IIRC, since I don't drive my Vette much at night, rotating the **** clockwise will make the lights brighter and full rotation will also turn on the interior lights as well. Are you aware that the headlight dimmer switch is located at the upper left of the toe board?
Wow, I have owned my vette for a few years and I never knew about rotating the **** and dimming the interior lights. As for the headlight dimmer, I didnt know about that either. What does that look like?
Burning Brakes
Joined: Mar 2013
Posts: 750
Likes: 180
From: Springfield Missouri
A dimmer switch I found on eBay and they can be found at your local auto parts store.
https://www.ebay.com/sch/i.html?_fro...witch&_sacat=0
https://www.ebay.com/sch/i.html?_fro...witch&_sacat=0
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Melting Slicks
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From: Springfield Missouri
the dimmer switch is the OLD style, where you have to step on it with your FOOT, surely you have driven an older car with this style?? bUT THE TAIL LIGHTS NOT WORK COULD BE A FUSE(DID YOU CHECK WITH A TEST LIGHT OR VOLTMETER ACROSS THE FUSE?).Sorry about the caps. Did you check the light sockets for 12 volts?? No 12 volts, then start checking back to the headlight switch(then replace it).
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The 'Taillight' fuse feeds the 'instrument panel lights.
As said above, check BOTH sides of the fuse holder to prove that power is on both sides.
As said above, check BOTH sides of the fuse holder to prove that power is on both sides.