Contact resistance and oxidation

Fig 1: Inspecting Terminals

Courtesy of VOLVO CARS OF NORTH AMERICA.

In theory, the resistance across contacts, leads and terminals should be 0 Ω. However, there is always some resistance due to terminal oxidation.

If resistance is too great there will be function problems. The magnitude of the resistance before it causes a malfunction depends on the circuit load. A guideline would be a few ohms.

Cleaning female socket terminals and male pin terminals

Fig 2: Apply Rust Solvent Spray Or Grease To Connectors

Courtesy of VOLVO CARS OF NORTH AMERICA.

NOTE:

Do not apply rust solvent spray or grease to the catalyst monitor sensor or instrument cluster connectors.

Ignition off
Disconnect the battery negative terminal
Use compressed air to clean the disconnected connector
Apply rust solvent spray 1161422 to the disconnected connectors
Blow clean using compressed air.

Greasing female terminals

Fig 3: Pressing Grease Into Terminals

Courtesy of VOLVO CARS OF NORTH AMERICA.

NOTE:

Do not fill the protective cover with grease.

Press grease, P/N 1161417-9, into the terminals directly from the tube
Check that all the cavities in the connectors are filled
Use a loose male pin to ensure that contact in sockets is good. The pin should remain in position when pulled gently.

Fig 4: Using Loose Male Pin To Ensure Contact In Sockets Is Good

Courtesy of VOLVO CARS OF NORTH AMERICA.