alternator or AC clutch?

[NigeB]

Hi folks, so...... out collecting a chinese takeaway this evening (always take the Z... lovely windy road and 40 minute round trip) - it was dark so clearly I had the headlights on.

I noticed that every couple of minutes the headlights dimmed momentarily........I was really confused until I realised that I had the AC on and the dimming coincided with the AC clutch kicking in.......

So, the question is....do I had a dodgy voltage regulator or a dodgy AC clutch? or both!!!!!!

Any thoughts?

 

[colb]

Put a voltmeter on the battery with the engine running to see what the alternator is putting out, should see at least 14.5 volts with revs. Keep the voltmeter connected and watch what happens when the AC kicks in, try it with and without the headlights on to see if they make a difference. Could be the alternator is on the way out.

 

[Rudyrov]

That sounds more like a battery problem, its suppose to have the reserve power your car needs for sudden demands.
Could also be bad grounds to the engine.
But, don't discount the alternator, test it.

 

[NigeB]

Put a voltmeter on the battery with the engine running to see what the alternator is putting out, should see at least 14.5 volts with revs. Keep the voltmeter connected and watch what happens when the AC kicks in, try it with and without the headlights on to see if they make a difference. Could be the alternator is on the way out.

I will have a look tomorrow - battery is only 6 months old so shouldn't be that. Thanks for the advice

 

[NigeB]

That sounds more like a battery problem, its suppose to have the reserve power your car needs for sudden demands.
Could also be bad grounds to the engine.
But, don't discount the alternator, test it.

Thanks for your thoughts - I like the sound of a bad earth - could be the culprit......I will have a play over the weekend to see what is going on.