Electrical problem?

[TheSnowman]

Hello
2018, Transit 350, L3 H3
Occasional problem. The off side indicator flashes quickly on the dashboard but not on the front or mirror. Sometimes returns to normal speed after a few flashes. At the same time the heater fan stops working.
Everything returns to normal when I switch off the engine and back on again.
Also occasionally when parked the horn sounds when I lock although all doors are correctly closed.

Any suggestions appreciated