Just bought a 2005 yaris petrol 1.3

[m456an]

It seems to run fine, though I have not insured it. Took it round the block a couple of times. So clutch is not slipping and no wheel bearing noise. Seems to drive OK and has no engine faults when connected to torque pro.

The guy who we bought it from had fixed a broken fog light it seems with a cloudy second hand one. And the wife noticed cellotape under the fog light where a light is on other side.

Anyway a good deal for 950 pounds with 60700 miles.

But one problem,

when I switch on the lights I hear a vacuum cleaner machine sound, which stops when I switch off the lights.

 

Does it have a weak Battery and the alternator is working harder, and the belt turning faster? But there is no warning light for weak Battery?

[unclepoo]

You could try turning the lights on without the engine running. See if there is still any noise.

It could be that the alternator is on its way out. My daughters yaris alternator failed and its the same age as yours.

Oh, and grease the brake pipes too....they are a common mot fail due to corrosion.

[m456an]

Thanks I will try to check under the car for the break pipes, and I do have a large jar of comma general grease I believe it is white lithium based so it is suitable for metal.

I have cleaned the Battery terminals and used a battery and alternator tester and it says both are good.

Also coolant was below the low mark, but I had some pink coolant that I bought for my avensis.

I also cleaned a connection going towards the fog light that was fixed  but light still works when I disconnected it and sprayed it with contact cleaner.

Then I thought I will try moving and touching things to see how it affects the whining sound, I touch that connection that I cleaned before and the noise changed, moved it a little and the noise stopped.

[Madasafish]

Could be a relay chattering.. Open bonnet and listen near fuse box..  or grovel in drivers side footwell, remove cover to fusebox and listen.

[m456an]

will do.