I have a 2001 Honda Accord EX and this morning the brake light came on- the handbrake is not up, and the brakes work fine. Could it be just a sensor from the intense cold here in jersey today (12degrees)? Or is it something more serious. Looking for some help... thanks for your time.

 

That warning lamp is also triggered by brake fluid level in the reservoir. Check that. Possibly the float switch in the reservoir cap is hanging on something?

If not, then check for a bent bracket on the switch at the brake lever.