Find and fix an automotive short circuit
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Photo 1. Connect the tester
Yank the fuse for the shorted circuit and install a fuse adapter. Then connect the circuit breaker leads to the adapter.
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Photo 2. Trace the circuit
Slide the meter along the wiring harness and watch the needle swing back and forth. When it stops swinging, you're at the short.
Finding and repairing a short circuit in your car or truck's electrical system can cost $200 and up at a shop. But if you spend $15 on a pro-grade shop manual and $40 on specialty tools (see our sources below), you can track it down yourself in an afternoon.
Install the adapter and breaker in the fuse box (Photo 1). Then find the short with the meter (Photo 2). Open the wiring harness and locate the chafed or shorted wires and repair them with electrical tape. Reinstall the fuse and test the circuit.
The tools you'll need
Finding the exact spot where electrical current stops flowing used to involve at least a little guesswork, but modern automotive electrical tools make pinpoint identification possible. Here's where to find the tools we used:
KD Tools 2524 Short Circuit Detector, available at sears.com
GTC CT6100 Fuse Socket Connector Kit, available at amazon.com
Digital shop manual for the year, make and model of your car or truck, available at eautorepair.net