All about Ford Mondeo

Battery leads - check and renewal
Engine electrical systems / Battery leads - check and renewal

Note: See also the relevant Sections of Chapter 1.

1 Periodically inspect the entire length of each battery lead for damage, cracked or burned insulation, and corrosion. Poor battery lead connections can cause starting problems and decreased engine performance.

2 Check the lead-to-terminal connections at the ends of the leads for cracks, loose wire strands and corrosion. The presence of white, fluffy deposits under the insulation at the lead terminal connection is a sign that the lead is corroded and should be renewed. Check the terminals for distortion, missing clamp bolts, and corrosion.

3 When removing the leads, always disconnect the negative lead first, and reconnect it last (see Section 1). Even if only the positive lead is being renewed, be sure to disconnect the negative lead from the battery first (see Chapter 1 for further information regarding battery lead removal).

4 Disconnect the old leads from the battery, then trace each of them to their opposite ends, and detach them from the starter solenoid and earth terminals. Note the routing of each lead, to ensure correct installation.

5 If you are renewing either or both of the old leads, take them with you when buying new leads. It is vitally important that you replace the leads with identical parts. Leads have characteristics that make them easy to identify: positive leads are usually red, larger in cross-section, and have a larger-diameter battery post clamp; earth leads are usually black, smaller in cross-section and have a slightly smaller-diameter clamp for the negative post.

6 Clean the threads of the solenoid or earth connection with a wire brush to remove rust and corrosion.

7 Attach the lead to the solenoid or earth connection, and tighten the mounting nut/bolt securely.

8 Before connecting a new lead to the battery, make sure that it reaches the battery post without having to be stretched.

9 Connect the positive lead first, followed by the negative lead.

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