Hello all. I bought a 2001 S80 the other day...and we put a new battery on it. Drove it most of the day, worked fine. Got home and after about 2 hours went to start it, it wouldn't start. Jumped it off, worked fine...later the same thing. Next morning, jumped it off worked fine...after parking it and went to leave again a few hours later..it was dead. When you turn it off, you can hear a buzzing sound in the ac/radio panal like it isn't turning off but yet we turn the ac and radio off. The check engine light has came on and the little red triangle is also on. Does anybody know what could be draining my battery so quickly?

 

You might have a bad relay somewhere. Track down the clicking noise.

 

Howdo I do this? Please tell me where to start on finding the problem. I just want my problem solved. The clicking noise is when I try to start it, all it does it click, it doesn't even try to turn over or anything.
Sorry I didn't make myself clear on that.

 

Start with checking the battery terminal connections and that they are tight. Also I believe when the red triangle is illuminated there should be a message displayed in the information window, what does it say? If you know someone with a code reader plug that in and see why your check engine light is on.

 

the message is something to the effect of "bulb need to be adjusted" and yes the terminal connections are tight. Something drains the battery in 2 to 3 hours. Runs perfect and will start if it is only left off for 20 to 30 minutes.

 

Ok if it only clicks when you try to start it may be something else.
You need to do or have a parasitic draw test done.