Bad bulb or wiring or internal contact on the signal switch that creates either too much or too little resistance for the flasher to work properly. Right side works ok, right? This points away from the flasher unit itself.
On a bimetallic flasher it needs the correct amount of current to flash at the correct rate, since it is constantly heating and cooling a bimetal strip, which makes and breaks the circuit. It is very sensitive to circuit load. Fast flashing indicates over current. No flashing indicates low current.
An electronic flasher unit has an internal circuit which doesn’t rely on the external load to determine it’s flash rate.
I’m not sure which one you’re supposed to have.
Lamps can get shorted but still light up. Wiring can have a partial pathway to ground. Both these things increase current.
But, because you said it will sometimes not flash at all, it seems to me that there is likely a problem inside the signal switch itself.
A person has to pull the steering wheel to get access to that switch. Not an insignificant job.
Should also check for DTC’s.
That should get you going on troubleshooting.
On a bimetallic flasher it needs the correct amount of current to flash at the correct rate, since it is constantly heating and cooling a bimetal strip, which makes and breaks the circuit. It is very sensitive to circuit load. Fast flashing indicates over current. No flashing indicates low current.
An electronic flasher unit has an internal circuit which doesn’t rely on the external load to determine it’s flash rate.
I’m not sure which one you’re supposed to have.
Lamps can get shorted but still light up. Wiring can have a partial pathway to ground. Both these things increase current.
But, because you said it will sometimes not flash at all, it seems to me that there is likely a problem inside the signal switch itself.
A person has to pull the steering wheel to get access to that switch. Not an insignificant job.
Should also check for DTC’s.
That should get you going on troubleshooting.
