Weird sound from car

[matthew_o50]

My dad took his car out this morning and noticed a strange sound coming from it, it's like a faulty exhaust kind of sound but it noticeably changes whenever something electrical is touched such as the windows or wipers and is worse when idoling. The noise is definately outside the car and from what I can tell, it is coming from near the back. What do you guys think it could be? It's a Daihatsu Terios 1.3+ with only 22k on the clock. It just had a full service a few weeks ago and has been perfectly fine up until today.

Thanks

Matt

 

[iCraig]

Alternator perhaps?

 

[matthew_o50]

Is there anyway you can tell when the alternator is going? To me the sounds like its not coming from the engine but from close to the back of the car on the drivers side