Tail lights brighter than turn and brake lights

[Robliepse]

The brake lights and turn signals in my 72 Roadrunner work as expected with and without my head lights / tail lights turned on. The issue I’m having is my tail lights are brighter than the turn and brake lights so you can’t notice them blinking at night when the tail lights are on. You can barely see them over the. Tail lights. Could I have the wrong bulbs?

 

[mopar 3 B]

Are your bulbs 1157's.

 

[road chicken]

Voltage is the same going to both ,so the filiment size is the difference. Pop the lens off and see . The larger one is lighting for your brakes/ turn and the smaller for your markers. If not figure out why...and checking for 1157 on the bulb is the first place to start. If they are 1157s ( which are indexed by the difference between the Brass pins on the outside) make sure they are in properly...loose sockets can allow the to go in bsckwards. If ok....it is possible the internal connection in the bottom of the socket got rotated 180 degrees somehow. Last item, and very remote, would be the bulbs were made wrong. Not likely but anything is possible. Good luck

 

[Robliepse]

Thanks, I thought the wrong filaments were being used within the bulbs. It’s happening the same on both sides so I’ll check the PN# then the wiring. The harness was new but I still have the original for reference

 

[66383]

GROUNDS!! Check 'em ALL.

 

[mopar 3 B]

So a new wiring harness was installed. If the problem is not the ground wire in the trunk. Someone did not wire the new harness correctly. Check the plug at the drivers side seat and see if the plug is wired correctly.

 

[khryslerkid]

Now that it was stated that a new wireing harness was used, sounds like the wires are backwards.

The heavy element (brake lights/turn signal) is wired to parking light and the parking light circuit is wired to the brake/turn signal.

 

[Robliepse]

Agreed, but it’s on both sides and tail lights are tied together. I’ll figure it out tomorrow and post my findings

 

[road chicken]

If everything checks out ok with the mechanical stuff, it may be just as simple as swapping the wires at the harness plug that feeds the rear lights. The wire colors should be the same on both sides. Check your old harness for the correct order.

 

[72RoadrunnerGTX]

On the ’72, the tail light harnesses are not being reproduced. Originally serviced as part of the tail light housings, sockets and connectors are sealed. By “new harness” I assume you mean the body harness from the driver’s kick panel to the rear bumper. The correct 1157 bulb should only key in one way, the low watt filaments should be all wired to the park circuit. The park circuit is the only circuit connected to all four tail light bulbs, license plate lamp, and the right side marker. The, two per side, left and right high watt turn signal/stop light filaments are wired separately. A single reversed connection somewhere is not likely. Either the wrong bulbs or the tail light harnesses have been rebuilt/rewired incorrectly.

At the body harness connector;

Grey - ground

Black - park lights

Dark Green – left turn/stop

Brown - right turn/stop

 

[Rusty 72]

^^^^^^^
This.
When I rebuilt my 72's taillight harness because yeah they don't sell them, I almost wired it backwards. The turn/stop lights are the same filament which is brighter than the smaller filament- taillights. Sounds like yours is wired for the brakes on the larger filament and the taillights/turn are wired together.
Good luck.