Tomberlin turn signal problem

[grehder]

Left turn signal stays lit (no blinking) when turned on.

2010 Tomberlin Emerge (48V with eight 6-volt batteries):

When turned on my left FRONT turn signal stays lit rather than flashing on & off. Both the right front & rear turn signals work fine, as does the left REAR turn signal. The dash light for the left turn signal stays on (rather than flashing) even though the left REAR turn signal is flashing on & off at the same time the front left turn signal stays lit.

Is this a grounding/wiring problem? Is it a problem with the flasher?

I have switched the right front bulb for the left front bulb but it makes no difference. If the flasher is defective why do 3 of the 4 turn signals work fine? All the fuses are OK & it makes no difference whether the batteries are fully charged or not. Cleaning bulb connection points did not help. All wiring is factory done (no kits) & this is the first such problem in 3+ years of use. Since the bulb is OK I may replace the flasher next. The Tomberlin manual lists 4 possibilities for this problem (bulb, flasher, DC converter & combination switch failure). Is checking/replacing them one-by-one necessary?

Any suggestions would be appreciated.