C3 General General C3 Corvette Discussion not covered in Tech
Sponsored by:
Sponsored by:

Tail and dash lights out when lights on

Thread Tools
 
Search this Thread
 
Old 01-21-2018, 09:15 AM
  #1  
tjmaniez
Instructor
Thread Starter
 
tjmaniez's Avatar
 
Member Since: Apr 2016
Location: KC, MO
Posts: 138
Received 10 Likes on 7 Posts
Default 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?
Old 01-21-2018, 09:26 AM
  #2  
ntfday
Pro

 
ntfday's Avatar
 
Member Since: Mar 2013
Location: Springfield Missouri
Posts: 742
Received 178 Likes on 123 Posts

Default

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.
Old 01-21-2018, 09:32 AM
  #3  
tjmaniez
Instructor
Thread Starter
 
tjmaniez's Avatar
 
Member Since: Apr 2016
Location: KC, MO
Posts: 138
Received 10 Likes on 7 Posts
Default

Originally Posted by ntfday
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.
Old 01-21-2018, 10:57 AM
  #4  
ntfday
Pro

 
ntfday's Avatar
 
Member Since: Mar 2013
Location: Springfield Missouri
Posts: 742
Received 178 Likes on 123 Posts

Default

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
Old 01-21-2018, 12:31 PM
  #5  
tjmaniez
Instructor
Thread Starter
 
tjmaniez's Avatar
 
Member Since: Apr 2016
Location: KC, MO
Posts: 138
Received 10 Likes on 7 Posts
Default

Originally Posted by ntfday
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
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.
Old 01-21-2018, 12:44 PM
  #6  
ntfday
Pro

 
ntfday's Avatar
 
Member Since: Mar 2013
Location: Springfield Missouri
Posts: 742
Received 178 Likes on 123 Posts

Default

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?
Old 01-21-2018, 01:40 PM
  #7  
tjmaniez
Instructor
Thread Starter
 
tjmaniez's Avatar
 
Member Since: Apr 2016
Location: KC, MO
Posts: 138
Received 10 Likes on 7 Posts
Default

Originally Posted by ntfday
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?
Old 01-21-2018, 02:15 PM
  #8  
ntfday
Pro

 
ntfday's Avatar
 
Member Since: Mar 2013
Location: Springfield Missouri
Posts: 742
Received 178 Likes on 123 Posts

Default

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
Old 01-22-2018, 03:11 PM
  #9  
ntfday
Pro

 
ntfday's Avatar
 
Member Since: Mar 2013
Location: Springfield Missouri
Posts: 742
Received 178 Likes on 123 Posts

Default

https://docs.google.com/viewer?a=v&p...2E5ZTkxMTc1NmY

Something I found that might be helpful
Old 01-22-2018, 04:21 PM
  #10  
Easy Mike
Team Owner
Support Corvetteforum!
 
Easy Mike's Avatar
 
Member Since: Jun 2000
Location: Southbound
Posts: 38,928
Likes: 0
Received 1,469 Likes on 1,248 Posts
Cruise-In II Veteran

Default

Originally Posted by tjmaniez
...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...
Order an owner's manual for your 76. Read through it when it arrives.
Old 01-22-2018, 08:38 PM
  #11  
lvmyvt76
Melting Slicks
 
lvmyvt76's Avatar
 
Member Since: May 2011
Location: Springfield Missouri
Posts: 2,755
Received 121 Likes on 118 Posts
Default

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??
Old 01-22-2018, 08:40 PM
  #12  
lvmyvt76
Melting Slicks
 
lvmyvt76's Avatar
 
Member Since: May 2011
Location: Springfield Missouri
Posts: 2,755
Received 121 Likes on 118 Posts
Default

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).
Old 01-22-2018, 09:08 PM
  #13  
Peterbuilt
Le Mans Master
 
Peterbuilt's Avatar
 
Member Since: Aug 2006
Location: mount holly NC
Posts: 6,989
Received 1,246 Likes on 966 Posts
C3 of Year Finalist (appearance mods) 2019

Default

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.

Get notified of new replies

To Tail and dash lights out when lights on




Quick Reply: Tail and dash lights out when lights on



All times are GMT -4. The time now is 04:35 PM.