I have a 1991 Corolla with 4AF carburettor engine. I have a problem where the fan doesn't turn on unless the fan switch (which is located near the thermostat) is unplugged. I thought that the problem was the fan switch, but today I was working on something unrelated and bumped a wire (pictured) next to the battery and the fan randomly started up. On looking closer, the box that the wires go into (pictured) is quite corroded making a dodgy connection. Clearly there is a problem here. Does anyone know what this thing is or how I could fix it (it looks like the insides of it are beyond repair)?
I am highly confused as to what this thing does.
Thanks in advance.