Tail lights not working. 1972 - Chevelle Tech
Electrical & Wiring Troubleshooting electrical problems.

 4Likes
  • 1 Post By DUTCH MAX HEADWORK
  • 1 Post By LevonH
  • 1 Post By Srober40
  • 1 Post By oldcutlass
 
LinkBack Thread Tools Search this Thread Display Modes
post #1 of 14 (permalink) Old Feb 15th, 20, 7:37 PM Thread Starter
Scott
 
Join Date: Jan 2020
Location: Texas
Posts: 14
Garage
Tail lights not working. 1972

Hey gang,

Newbie here. Have a question.

Rear tail lights do not work when lights are on. Brakes lights and turn signals work. Headlights and front markers work.

Any suggestions where to start?

Thanks

Scott
Srober40 is offline  
Sponsored Links
Advertisement
 
post #2 of 14 (permalink) Old Feb 15th, 20, 7:48 PM
Lifetime Premium Member
Al
 
Join Date: Apr 2011
Location: SO CAL...Huntington Beach and Rancho Cucamonga
Posts: 5,589
Garage
Re: Tail lights not working. 1972

License plate light. Got power there? Got power to the side marker lights? Taillights are on the same circuit.

Ground your test light to the bumper, pull the lightbulb and probe both contacts. See any power there. One should show constant power with just the taillights on.

BROWN wire is going to be the power wire for your taillights and license plate light. All on the same circuit.

If youR parking lights are working that means you are getting power from the headlight switch to the park lights and taillights. Both are supplied from the same circuit from the headlight switch LEADING THROUGH A BROWN WIRE.

Check your fuses with a test light on both sides of the fuse.
davewho1 likes this.

Last edited by DUTCH MAX HEADWORK; Feb 15th, 20 at 8:06 PM.
DUTCH MAX HEADWORK is offline  
post #3 of 14 (permalink) Old Feb 15th, 20, 8:50 PM
Moderator
Levon
 
Join Date: Jul 1999
Location: Priddis, Ab. Canada
Posts: 9,323
Re: Tail lights not working. 1972

Have you tested the bulbs?
davewho1 likes this.

Levon Hovagimian
Team Chevelle #279
2015 Camaro ZL1 Summit White (Bone Stock)
70 Chevelle SS 454 LS5 4 speed. SOLD
Current Engine VortecPro 460 (513 HP) Original is resting
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

1966 427 Corvette SOLD
1973 Camaro IHRA Hot Rod (LS-6 Auto)11.00 @121 (Chased a 10.99 or better) SOLD

Priddis Greens, Ab. Canada


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
LevonH is offline  
 
post #4 of 14 (permalink) Old Feb 15th, 20, 9:15 PM Thread Starter
Scott
 
Join Date: Jan 2020
Location: Texas
Posts: 14
Garage
Re: Tail lights not working. 1972

Bulbs seem to be o.k. I didnít see broken filaments.

Need to check the side markers and license plate light now that it is dark.

Thanks for the replies.

I am learning as I go. I have a lot to learn.... I do use the search function on the forum. Lots of great info on this site.

I went and got new bulbs for all of the lights also. I figure if I donít need them, I will eventually.

I have lots of bugs to work out on the car. Mostly minor. Focusing on the ones needed for inspection first.
Srober40 is offline  
post #5 of 14 (permalink) Old Feb 16th, 20, 1:13 AM
Lifetime Premium Member
Kevin
 
Join Date: May 2009
Location: Maryland
Posts: 637
Re: Tail lights not working. 1972

You say brake lights work. Do the turn signal indicators on the dash light up when you press the brake pedal? If so, then you have a bad ground at the taillights.

2017 SS
1972 El Camino Custom
2005 SSR 6-speed
1999 Silverado
SSR71 is offline  
post #6 of 14 (permalink) Old Feb 16th, 20, 8:07 AM
Senior Tech Team
Jeff
 
Join Date: Jun 2009
Location: Pittsburgh, Pa.
Posts: 2,516
Re: Tail lights not working. 1972

Check the wiring harness connections. There's one around the back seat.. I cut the plugs off then solder and tape the wires..

Also look for the grounds and clean them up by removing the screws, wire brushing the area, then connect them back up and cover them in either wheel bearing grease or paint..
hydro462 is offline  
post #7 of 14 (permalink) Old Feb 16th, 20, 10:20 AM Thread Starter
Scott
 
Join Date: Jan 2020
Location: Texas
Posts: 14
Garage
Re: Tail lights not working. 1972

Thanks for the replies.

Bad ground and a bad bulb. All working now. Next step is to replace all of the bulbs since I have them.

Next step is to figure out how to get the horn to work....
DUTCH MAX HEADWORK likes this.
Srober40 is offline  
post #8 of 14 (permalink) Old Feb 16th, 20, 10:35 AM
Senior Tech Team
Eric
 
Join Date: Aug 2011
Location: Poteau, Ok
Posts: 4,678
Re: Tail lights not working. 1972

There is no reason to replace all the bulbs, just remove them and clean the sockets. The horn/s are powered by a relay that is looking for a ground supplied from the black wire fed from the horn button. The relay has 12v on it at all times and once it gets a ground signal it provides 12v to the horns. So you need to see which half of the circuit is not working, the ground side or the plus side.
DUTCH MAX HEADWORK likes this.

You're just jealous because you can't hear the voices!

1967 Olds Cutlass 468 BBC/T400
1963 Plymouth Fury 440/Torqueflite
2007 Ford Mustang GT (momma's car)
oldcutlass is offline  
post #9 of 14 (permalink) Old Feb 16th, 20, 8:06 PM Thread Starter
Scott
 
Join Date: Jan 2020
Location: Texas
Posts: 14
Garage
Re: Tail lights not working. 1972

Thanks.

The horn has a good ground. The steering wheel is a 4 spoke. I think it is missing an insulating ring and a plunger piece.

When I push the plunger in and ground it the relay clicks.

Need to check the wire running from the horn to the relay next.
Srober40 is offline  
post #10 of 14 (permalink) Old Feb 16th, 20, 10:21 PM
Senior Tech Team
Eric
 
Join Date: Aug 2011
Location: Poteau, Ok
Posts: 4,678
Re: Tail lights not working. 1972

If the relay clicks your half way there. Make sure there is 12v going to the terminal that the horn wire is hooked to. Then follow that wire and see where the 12v is lost.

You're just jealous because you can't hear the voices!

1967 Olds Cutlass 468 BBC/T400
1963 Plymouth Fury 440/Torqueflite
2007 Ford Mustang GT (momma's car)
oldcutlass is offline  
post #11 of 14 (permalink) Old Feb 17th, 20, 8:42 AM
Senior Tech Team
Jeff
 
Join Date: Jun 2009
Location: Pittsburgh, Pa.
Posts: 2,516
Re: Tail lights not working. 1972

Give the bulb a spray of WD before putting it in the socket, this also works for vacuum and water hose connections..
hydro462 is offline  
post #12 of 14 (permalink) Old Feb 20th, 20, 8:19 PM Thread Starter
Scott
 
Join Date: Jan 2020
Location: Texas
Posts: 14
Garage
Re: Tail lights not working. 1972

Thanks guys.

On the horn wire, what gauge is the right gauge to replace it from the horn to the relay?

Hydro462, I see you are from Pittsburgh. I was born and raised there. Spent the first 38 years of my life there. Grew up in the south hills.
Srober40 is offline  
post #13 of 14 (permalink) Old Feb 21st, 20, 10:01 AM
Senior Tech Team
Ed
 
Join Date: Aug 2013
Location: Pittsburgh, PA
Posts: 4,317
Garage
Re: Tail lights not working. 1972

Quote:
Originally Posted by Srober40 View Post
Thanks guys.

On the horn wire, what gauge is the right gauge to replace it from the horn to the relay?

Hydro462, I see you are from Pittsburgh. I was born and raised there. Spent the first 38 years of my life there. Grew up in the south hills.
There are a couple of us here! Pittsburgh, the #1 city in the country (to leave )
I've always been a east suburbs guy, out in Greensburg now.

1967 El Camino Malibu - Deepwater Blue
ZZ4 350, FiTech 600 complete!,Roadmaster tank, 700R4, Underdash A/C in progress, JGC Steering, 1990s truck serpentine.
Pioneer4x4 is offline  
post #14 of 14 (permalink) Old Feb 21st, 20, 8:15 PM Thread Starter
Scott
 
Join Date: Jan 2020
Location: Texas
Posts: 14
Garage
Re: Tail lights not working. 1972

Hey Pioneer.

I really like Pittsburgh. Great place to grow up and live. Loved the outdoor opportunities for hunting and fishing. Miss my friends and family. The winters are tough though.

Work took me to Texas and I like it here. Love the heat and mild winters.
Once I moved south I lost my tolerance for cold weather....
Srober40 is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Chevelle Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address. Note, you will be sent a confirmation request to this address.

Email Address:
OR

Log-in













Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome