You won't believe this! I pulled the reservoir tank and found that the wire connector at the bottom of the tank had been disconnected and shunted to bypass a faulty switch in the tank. In 2 1/2 years on the road the shunt began to work loose and the dash light came on intermittently. The car had about 6500 miles on it when I bought it, but it was titled as a new car with full warranty, etc. I got a great price and a fine car, but this kind of thing is pretty cheap; something you might expect from a Hyundai or Chevy dealer, but not Volvo (well, not any more). Since the car had never been outside of dealer service it had to be the dealer who did it. I suppose the switch cannot be replaced and the dealer would have had to install a new tank. Still, not a good recommendation. Think I'll talk to them about it and at least get $50 worth of embarrassment and foot shuffling out of them for my trouble. I just can't believe it!