Quirky indicator icons

I have 2002 Cadillac Seville SLS. From time the icons for the brake and abs do not go off after the call starts up. I’ll be driving for anywhere between a few minutes to an hour or so and they well go off and an audio tone goes off. Sometimes they will not come back on for the remainder of my trip, at other times times they will appear again then go off again. There is no indication that there is anything wrong with the brakes. Also, when the icons go off and the heater is on the fan will accelerate.
Any idea what may be going on?

Caddies tend to go into electronic overload…Your best bet might be to pull into a Caddy dealers service area when the lights are on…You have checked the brake fluid level, right?