Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Load Testing A Battery Or Ignition Feed Circuit
DIAGNOSTIC LOAD TEST (BATTERY/IGNITION FEED CIRCUIT)
- Disconnect the connector from the device(s) to gain access to the terminals and isolate the circuit being tested.multimedia:A supplement to the article is available.
- Using an approved connector back probe tool, connect the positive lead of the load test tool to the circuit being tested at point (A).
- Connect the negative lead of the load test tool to the negative side of the Battery or a good chassis ground.CAUTION:
Use only approved connector back probe tools when back probing a connector so as not to cause damage to the terminals or insulation of the connector. Damage to the terminals can cause poor terminal contact or retention. Damage to the insulation can introduce corrosion due to water intrusion.
Does the bulb light bright, as when compared to a direct Battery connection?
Yes
- The circuit being tested can carry a load, check other circuits, connectors and terminals for concerns.
No
- Repair the circuit, connector or terminal that has an open or excessive resistance.
- Perform any related Recalls or Service Bulletins that may apply.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.