Light problem!

[SSE]

My dads mate replaced extractor fan today in bathroom. But whenever he turns it on the light in the next room starts flashing/pulsing (his words not mine). I've yet to check it out and won't be until Sunday as it's twenty miles away unless he solves the problem before then. What could it be? Loose connection somewhere?

 

[telectrix]

bad connection or incorrectly wired.

 

[Richard Burns]

Yeah, loose connection in the light fitting for the loop to the light next door, failing under load.

 

[SSE]

bad connection or incorrectly wired.

Doubt it's the wiring as it was ok with the last fan.

 

[Short Circuit]

its the switched live and neytral the wrong way around in the fan - dont know why it does that, but it does!