SRS warning light in Honda CRV

I have a 2003 Honda CRV. The SRS warning light had intermittently come on last summer but now it remains on even after I restart the car. The dealer could not find a reason stating “malfunctioning warning light” and instructed me not to place anything (even a cell phone) on the passenger seat. I have noticed the light coming on with extremely hot weather…any suggestions?

Bad sensor…replace

dealer told me that it would be around $800 to replace SRS system, does that sound about right?