Used 3 stage damper block near handbrake for switch live (engine cut out,no dash lights buy turns over)


Used the connector block for 3 stage damper (under carpet near handbrake) for a switch live to run 10A heated seat, engine was running then something popped and everything went off. No dash lights but engine turns over. Put power back through connector and all lights come back on and runs fine. All fuses and fusible link in engine bay fine. Does anyone know what else is on this circuit that I could of upset? TIA