I have a brake warning light illuminated, my master cylinder is full, switch checks good for continuity, the parking brake switch checks good also, i checked the parking switch 12v and low fluid level switch power 10v , parking switch power wire to ground ,its an open , fluild level switch power wire to ground found 40000 ohms, it'* going to the cluster.. how can i check the cluster to see if the brake warning light is caused by the instrument cluster ?