Lights dim when electrics used.

[LoJac963]

There should be other frame (chassis) grounds also not just what is obvious in the engine compartment.

[fyr145]

Thats true...............I forgot to mention that.

stupid me........ my bad.

Thanks LoJac

[HUMTECH]

One other thing, still related to testing alternator. May be putting out but if one diode in alternator fails then it will only put out 2/3 of its regulated output, 2 diodes out 1/3 charge. Something to keep in mind when testing alternator output.

[smileynialley]

The battery was replaced last year. It starts first time no issues so the battery is good.
I thought it could be a bad earth/ground too but the lights dim when the windows are activated too. Does anyone know if the windows and the brake lights happen to share an earth?
I also mentioned that I've noticed a whirring noise coming from the front of the car which gets faster as the revs go up, I'm wondering if this is an alternator problem.

[MVR 155]

As the others mentioned... it sounds like the culprit is likely the altenator, have it tested.

[iwillnc]

Mine also dims with something as simple as windows being rolled up/down, doesn't really affect anything so I've just ignored it.

[LoJac963]

Originally Posted by iwillnc

Mine also dims with something as simple as windows being rolled up/down, doesn't really affect anything so I've just ignored it.

Mine has done that for a while also especially with rolling up all the windows at the same time. I'm sure the alternators are the issue but I still have normal volt output so I'm not concerned about it right now.

FYR where did you pick up your higher output alternator?