Left turn signal comes on when I turn the ignition then doesn't work

I am having the same issue on a 2005 FLHRCI Road King Classic. Basically the left turn signal comes on when I start the engine. It will not cancel by pushing the left turn signal button. However, if I push the right turn signal button the left will go off and the right will start blinking. Sometimes, this same action starts all four signals blinking (like the emergency flashers). It is very erratic. I have Kuryakan pancea rear taillights and brake light. The brake light went out so I went a bought a new brake/taillight with a new adapter. Brake lights work now but the blinker problems happens whether the back lights are connected or not. Front turn signals are stock.

Any help would be greatly appreciated.

Intermittent problems can be the most frustrating thing. This can take a lifetime to solve or a few hours depending on whether fault shows itself when working on bike. More than likely it will be a leaky turn signal switch. Problem caused by owners using pressure washers and power washing the hand controls etc. forcing water into switchgear. Power washers should never be used near electrical parts or wheel bearings as water will be forced passed seals causing corrosion and eventual failure.