You must visit your local friendly Volvo dealer in order to have th DRL's disabled. (it is a software change and the dealer will have to disable DRL)
Note: your service interval is factory set to 7500 miles and if you wish to perform oil changes earlier, say at 5000 miles, you'll also have to have the dealer change that for you as well. I had mine changed to 5000 miles and there was no charge from the Volvo dealer for doing this procedure.

now about that service light:
This procedure is for the 2002 V70 and I believe it still is the same for 2003
1) Turn ignition to postion I
2) Press and hold the trip reset button and wait for the trip mileage to reset to zero
3) While holding in the button, turn the key to postion II, and watch the trip miles.
4) When the previously displayed miles reappear, release the button.
you're all done !
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You will never leave where you are until you decide where you would rather be - 2002 V70 stk, /w /tinted windows