I am having a problem with my charging light coming on very dim when I use my wipers or blinkers. Is this caused by faulty grounds? I had my alternator tested they said it was good and I put in a new voltage regulator. any help would be great. Oh do you think I may need a bigger battery.

 

Is this at idle?
If so, does it go off when you increase the idle?
Probably the alt brushes.

 

what other symptoms are you having? hard starting? like the other gent said does your idle go up? could also be bad brushes and contacts they are the the two big killers very easy to rebuild and cheaper. have you tried cleaning you battery too? how old is the battery. usually batteries need to be replaced every 60 months or so. give or take how abusive you are to it, (i.e. letting it go dead a lot).