S40 Radio Draining the battery

Baxtermt · Post by **Baxtermt** » 05 Jan 2011, 03:42

Hi Everyone I have been to this site many, many times and I have now, finally, joined, thanks for all your help in the past.

Now my problem, well it’s actually a friend of mine, he is a sensible Volvo driver as well.

Just before Christmas his battery was flat, after a recharge it went flat again, now a new battery, same again, this was when he called me I did a few tests the battery was charging off the alternator so that was fine.
After a few more tests he was using 0.5Amps when the car was just standing with everything switched off locked and unlocked.
The 0.5 Amps was found to be the radio.

My Question
Has any one come across this before, is there anything that I can do or is it just a new radio?

Thanks in advance
Matt

by the way it's a 2002 S40 and the radio is the top spec with sat nav

Post by **precopster** » 05 Jan 2011, 04:17

0.5 amps is definitely going to drain the battery. Have you tried disconnecting the battery for more than 10 minutes to allow any residual current to drain out of the electrical systems? Then reconnect & measure the current draw through the fuse to the radio circuit.

How did you narrow it down? What other circuits share the radio fuse?

Did the tester measure current draw at both of the radio's power leads? (I'm assuming there is more than one power lead because modern radios usually have a live +12V and a Accessories +12V input. If so which of the two circuits was at fault?

Baxtermt · Post by **Baxtermt** » 05 Jan 2011, 05:24

Thanks for the reply mike
I narrowed it down to the battery by putting an ammeter in the earth line and then kept an eye on it while I pulled fuses. On the S40 there is a plastic block that holds three fuses 1 of which is the radio and when the block came out the current went to 0.03A which is what it meant to be, or there abouts. So I replaced each fuse, 1 at a time, till I got the current again and it was the radio.
Though out the day the battery was disconnected for long periods at times, he is a mate and we had to put the world to rights over a brew, and that can take hours, especially when it’s cold.
I took the cables out of the back of the radio and the only block that stopped the current flow was the main cable block.
With limited tools at home I cant test each cable and I don’t want to go cutting them just to see which cable it is just yet, if I have to I will but I thought I would try the great mind that is the thousands of minds, the internet (this site is great isn’t it)

Post by **precopster** » 05 Jan 2011, 05:35

Baxtermt wrote:Thanks for the reply mike
I narrowed it down to the battery

Hmm you mean the radio??

Baxtermt · Post by **Baxtermt** » 05 Jan 2011, 11:05

Sorry, you got it, Radio......Radio.......Radio
I will get it right one day