Depending On Batt
Check the Batt, it may read ok when you test it with the car on, but even when it reads ok, it could be completely drained. I had a problem once, and i tested the Alt and Batt twice, both times they both read good voltage....Turned out that my batt was completely drained even though the computer said it was fine. When i changed the Batt, everything was fine.
I had so many people deny that it was the batt and everyone told me i would be wasting money if i bought one, even my father said so......well guess what? they were all wrong, i went with my gutt and remember you know your car better than anyone.
Beirutsfinest