Sequential lights in 1973 cougar

Good day,…yet another question about sequential lights. I have a 1973 Cougar. The passenger side sequential lights work perfectly, but the drivers side sequential light does as follows - BOTH INNER AND MIDDLE LIGHTS COME ON AT THE SAME TIME,…THEN THE OUTER LIGHT COMES ON…BUT VERY DIM. This stays the same with the headlights on, or off,…brake lights on or off, and emerg. flashers on or off. I have changed out the trunk black box flasher assembly on the drivers side,…but problem stayed the same. Any suggestions??? Thanks

Just to verify, your not doing LED lights. My first stop would be here for trouble shooting

Thanks very much for your response. These are original lights, not LED lights. Thanks for the link to solve these problems. I will certainly take a look tomorrow and let you know what I find.