Contact resistance and oxidation

Fig 1: Inspecting Terminals

Courtesy of VOLVO CARS OF NORTH AMERICA.

For repair of wiring and terminals, see appropriate repair information in CABLES AND FUSES - REMOVAL, REPLACEMENT AND INSTALLATION .

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

If this resistance becomes too great the result will be a malfunction. The magnitude of the resistance before it causes a malfunction depends on the circuit load.

Checks:

Check the cables visually according to Check terminals visually .

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:

Note Do not fill the protective cover with grease.

Press grease, P/N 1161417-9, into the female sockets directly from tube
Check that all the terminal cavities are filled
Use a loose male pin to ensure that the connection in the 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.