Why does my battery light come on and my steering fail after driving through a puddle?

Dear Car Talk

Dear Car Talk | Nov 01, 2001

Dear Tom and Ray:

Today I was driving to work in a nasty rainstorm. As I was driving
over the large puddles of water collecting on the roadway, something
strange happened. The red "battery" light on my dashboard lit up,
and I had a hard time steering my car around the curve ahead. Once I
got over the puddle, the problem stopped -- at least until I hit the
next puddle, when it happened again. I drive a 1990 Chevy Celebrity
station wagon. Is this something I should worry about? -- Vic

TOM: Steering? Nah. That's not important, Vic. Steering has always
been vastly overrated.

RAY: Don't listen to him, Vic. Here's what's happening: You have a
single belt that drives all of the accessories in your car. It's a
called a serpentine belt, because it's, well, serpentine. It slinks
all over the engine, around various pulleys, like a snake, and it
replaces all of the individual belts that used to run the

TOM: And when you drove through those puddles, that serpentine belt
got wet and started to slip. And when it slipped, all of the
accessories lost power, including the alternator (which is why the
battery light came on) and the power-steering pump (which is why you
had a hard time steering).

RAY: After a few seconds on terra firma, the belt dried out enough
to catch, and everything was fine again.

TOM: My guess is that it might be time to replace your belt. It
might be stretched or glazed, and all it took was a little water to
push it over the edge and make it slip.

RAY: If the belt was recently replaced, or if your mechanic inspects
it and says it looks fine, then you might need a new belt tensioner
-- which is supposed to automatically keep the belt at just the
right tension so stuff like this doesn't happen. Good luck, Vic. And
get it taken care of.

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