Caterpillar — Wiring Harness (Open Circuit) - Test
Testing & diagnosis · Genset wiring harness
From a Caterpillar service manual covering: BRK1-Up, CAL1-Up, CMC1-Up, CNB1-Up, FDN1-Up. Check it applies to your exact model before use.
Applies to: Caterpillar EUI Engine engine
Procedure
- Identify the connectors and wire numbers of the suspect circuits using the Electrical System Schematic.
- Turn the disconnect switch to the OFF position.
- Disconnect the components and the ECM from the wiring harness.
- Place a jumper wire from the contact of the suspect wire to frame ground at one disconnected harness connection.
- At the other connector, measure resistance from the contact of the suspect wire to frame ground.
Tools required
- Digital multimeter Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Resistance should be less than 5 ohms (OK)
- Greater than 5000 ohms indicates an open
Source: Caterpillar service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.