How to Use the MRCARTOOL B550 Automotive Circuit Tester

Connect the B550 safely, use multimeter, oscilloscope and frequency modes, simulate a controlled 0–5 V sensor signal and activate only identified loads with the correct current limit.

Connect the B550 safely, use multimeter, oscilloscope and frequency modes, simulate a controlled 0–5 V sensor signal and activate only identified loads with the correct current limit.

Connect and self-test the B530, select DC, AC, resistance or tone mode, read polarity and continuity, respond to the circuit breaker and keep power injection away from unknown or protected vehicle circuits.