Wiring Harness (Short Circuit) - Test
短路是一种可以导致意外电流的电路故障。 通常,短路是指绕过负载电路。 例如,指示灯电路导线之间短路会在导线中产生过大电流,但指示灯上却感知不到电流。 指示灯短路。 正常电路中的电阻值可能会发生变化,但是特定电路与其他无关电路之间的电阻值应始终大于 5000 欧姆。 下述步骤将说明短路测试:
参考有关完整的电气示意图,参考正在维修的机器的电气系统示意图。
测试是否存在短路。
- 确定可疑电路中的接头和导线编号。 使用机器的电气系统示意图检查电路。
- 将钥匙起动开关和断路开关转到断开位置。
- 从配线线束上断开部件和 ECM。
- 在 ECM 机器线束接头上,将一支万用表表笔放在可疑导线的触点上。
- 使用另一支万用表表笔检查 ECM 接头中的所有其他触点与机架接地之间的电阻。
预期结果:所有电阻测量值都大于 5000 欧姆。
确定 - 所有电阻测量值都大于 5000 欧姆。 线束电路正常。
停止。
异常 - 电阻小于 5 欧姆。 机器线束中存在短路。 可疑导线与具有最低电阻测量值的导线之间短路。
修理:修理或更换机器线束。
停止。
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