On the fuel pump relay there is a FT signal, I would like to know what it is, and where the signal comes from, what it is the function.
Can it create stalling if faulty signal is delivered?
car is W124 260E 1988 euro.
Many thanks to those who can help to understand

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Present cars:
My car: E-class 420CDI, 2008, W211, V8, 180 000km

Wife's one: C-class 220CDI Sport Coupé, Euro, 2002, W203. 345 000km

Son's one: GLK class, 220CDI, 2009, W204

Sold: E-class 260E, 1988, W124, Wonderfull car sold after 489 000 kilometres of reliable services (engine M103, clutch, brake system and 5 speed manual gear box all original).

Sold: E-class, 320CDI, W210, 2000, 225 000km