I have a 1993 that recently went through a car wash in the cold (not sure why). It was below freezing that day, and has not crossed 30 since that day as well. Since then, the ABS light is coming on and staying on at times. Not every time it is driven, but ~50% of the time. Occasionally the Brake light will come on as well.

I checked all the fluid levels and they are fine, and there is no fluid to be seen on the floor below the car. The brake pads were well within spec last month so I don't see that as the problem either. Our garage has not made it above freezing since then either. Could the sensors have ice or something else on them causing this to misread? If I have to, I'll purchase a heater to warm the garage to fix the problem.

Don't want to drop a lot of money to have a garage look and find no problem.

Thanks