Nothing in the short term. (It's "just" a warning light) but should be replaced ASAP.
If the connector is broken, replace the connector (can't remember if it's a plain Lucar -- peanuts -- or a "proper" connector -- scrappy), if the switch is fubar, new switches are pretty cheap.
thx its just i wont have the time to do it anytime soon so just the warning light will be on? will there b anyloss in power from he engine because last night i couldent get passed 30 but i think that was down to the timeing as the belt wasent tight enough whn i put it back on also it was amazingly hot in the engine bay
just had look at belt tightend it has look at timeing think its right the one on crankshaft is lined up to a ridge just near it theres 4 of them and i did it to top one still running rough at idle and has no power at low revs fort i better come in as its now 2 in the morning