[rocks66ss]

I have a friend who has a 64 Impala, has had it since new. BTY, it a 409/425hp 4 speed convertible. Over the years he has done some questionable things to it.

Here is the problem. There are 3 tail lights, the center one originally being a backup light. years ago he decided he wanted the center light to be a tail light, turn signal, brake light just like the outer and inner light, so he tapped into the inside light and added a socket for a 1157 bulb and turned the center backup light into a tail light, he did replace the white lens with a red one.

Fast forward to this weekend. he brought it to my house and asked me to replace the socket for him because the metal tab had broken and to make ground he had a piece of aluminum foil wedged in there.

After replacing the socket and bulb, it functions, but it is not nearly as bright as the light on the far outside. I didn't see it before so I don't know if all three lights were the same brightness to start with.

Any suggestions on why the center light that's tapped into the inside light is not as bright as the far outside tail light. I have made doubly sure the sockets are grounded well. What am I missing?


Rocky

 

[O'Man]

I have a friend who has a 64 Impala, has had it since new. BTY, it a 409/425hp 4 speed convertible. Over the years he has done some questionable things to it.

Here is the problem. There are 3 tail lights, the center one originally being a backup light. years ago he decided he wanted the center light to be a tail light, turn signal, brake light just like the outer and inner light, so he tapped into the inside light and added a socket for a 1157 bulb and turned the center backup light into a tail light, he did replace the white lens with a red one.

Fast forward to this weekend. he brought it to my house and asked me to replace the socket for him because the metal tab had broken and to make ground he had a piece of aluminum foil wedged in there.

After replacing the socket and bulb, it functions, but it is not nearly as bright as the light on the far outside. I didn't see it before so I don't know if all three lights were the same brightness to start with.

Any suggestions on why the center light that's tapped into the inside light is not as bright as the far outside tail light. I have made doubly sure the sockets are grounded well. What am I missing?


Rocky

It likely is wired in parallel with the other light.

 

[Coppertop]

It likely is wired in parallel with the other light.

I sure hope it is!

I think you meant in series. But, both the middle and the inner would be dim as they would both only be seeing half the battery voltage.


Rocky-

How dare you ask this here! Afterall, we have a sister Impala Tech site! l
l

Couple of thoughts....You may have the socket grounded good, but how good is the ground to the sheet metal? If memory serves me correct The inner and middle are apart of the trunk lid. Did GM run a dedicated ground to ensure the lights are grounded, or did they just depend on the hinges and latch to make "enough" ground. You're pulling more current now.

Also, if this is an original car, maybe the inner wire feed has a questionable connection so the extra current being pulled thru it is now showing up as a dimmer lamp. Bulbs are like snowflakes, they maybe the same type, but some can appear dimmer then others when there is a voltage feed issue.

How is the tail light brightness??? I'm assuming you're seeing the brake/turn brightness being affected??

Anything different between the left and the right trunk lid mounted lamps/wiring/factory grounds????

 

[O'Man]

I sure hope it is!

I think you meant in series. But, both the middle and the inner would be dim as they would both only be seeing half the battery voltage.


Rocky-

How dare you ask this here! Afterall, we have a sister Impala Tech site! l
l

Couple of thoughts....You may have the socket grounded good, but how good is the ground to the sheet metal? If memory serves me correct The inner and middle are apart of the trunk lid. Did GM run a dedicated ground to ensure the lights are grounded, or did they just depend on the hinges and latch to make "enough" ground. You're pulling more current now.

Also, if this is an original car, maybe the inner wire feed has a questionable connection so the extra current being pulled thru it is now showing up as a dimmer lamp. Bulbs are like snowflakes, they maybe the same type, but some can appear dimmer then others when there is a voltage feed issue.

How is the tail light brightness??? I'm assuming you're seeing the brake/turn brightness being affected??

Anything different between the left and the right trunk lid mounted lamps/wiring/factory grounds????

Yup typo...brain fart.

 

[rocks66ss]

I sure hope it is!

I think you meant in series. But, both the middle and the inner would be dim as they would both only be seeing half the battery voltage.


Rocky-

How dare you ask this here! Afterall, we have a sister Impala Tech site! l
l

Couple of thoughts....You may have the socket grounded good, but how good is the ground to the sheet metal? If memory serves me correct The inner and middle are apart of the trunk lid. Did GM run a dedicated ground to ensure the lights are grounded, or did they just depend on the hinges and latch to make "enough" ground. You're pulling more current now.

Also, if this is an original car, maybe the inner wire feed has a questionable connection so the extra current being pulled thru it is now showing up as a dimmer lamp. Bulbs are like snowflakes, they maybe the same type, but some can appear dimmer then others when there is a voltage feed issue.

How is the tail light brightness??? I'm assuming you're seeing the brake/turn brightness being affected??

Anything different between the left and the right trunk lid mounted lamps/wiring/factory grounds????

Joe,
It is all the time. When you turn the headlights on, the tail light is brighter on the outside than the center and inner that on the trunk lid.

Like I said I just replaced what was there, I cut the old socket wires, Black & White, and hooked the new socket exactly like it was, Black to black, and white to white. It was a replacement socket just like that had been previously replaced.

Is it possible that the center socket in question that was replace, that is tapped off of the inside socket which is the end of the line, has the wires on the wrong side? Because like I said I just replace what had already been one before me exactly like it was. So if that was the case, if I removed the bulb from the center socket, would the inside one get brighter?


BTW, I did go to the sister sight, and the last time I had been there was 7/3/2011 But I decided to come here where the real experts are :yes:

Rocky

 

[Coppertop]

Joe,
It is all the time. When you turn the headlights on, the tail light is brighter on the outside than the center and inner that on the trunk lid.

Like I said I just replaced what was there, I cut the old socket wires, Black & White, and hooked the new socket exactly like it was, Black to black, and white to white. It was a replacement socket just like that had been previously replaced.

Is it possible that the center socket in question that was replace, that is tapped off of the inside socket which is the end of the line, has the wires on the wrong side? Because like I said I just replace what had already been one before me exactly like it was. So if that was the case, if I removed the bulb from the center socket, would the inside one get brighter?


BTW, I did go to the sister sight, and the last time I had been there was 7/3/2011 But I decided to come here where the real experts are :yes:

Rocky

Rocky,

I'm leaning more towards issues with the 50 year old factory connections and splices...If you remove the factory brake/tail light bulb in the trunk lid completely, does the light "you added" get brighter? You may have to dig deeper and pull the rear lighting harness connections apart and clean/inspect.

I guess what I would have probably done is on the "modified" back-up light is install the 1157 socket, BUT, use the existing back-up light feed wire to feed the "stop/turn" filament and then tap into the tail feed in the existing bulb. You'd have to cut the back-up feed inside the car and then tap into the stop/turn wiring, but it would relieve some of the burden. You have to remember, the way your friend has it set-up it is really pushing it. When hitting the brakes and all 6 lamps come on, that brake circuit is pulling close to 12 amps!