Explain the function of the relay in a vehicle?

I know theoretically how a relay works and I know about a magnetic coil, armature, working current, control current, working current contact, etc. But ultimately I don't understand how a relay works in a car. Especially after the statement: The advantage of a relay is that you can switch large currents with it??? How large…

If one or two electrolytic capacitors (in the power supply) in a DDR radio fail, do the transistors for IF, RF, etc. also fail?

At the weekend I swapped the FM tuner from one complete unit to a defective one, and the other tuner to the complete unit. The result: the one that worked before didn't work with the FM tuner from the defective one. When I put the old one back in, it worked again. The defective one…