Good little 'HOW TO" on fuses

[Garth]

General information on fuses


All electrical circuits are protected by a combination of fuses and circuit breakers. Some vehicles also use fusible links. There are two fuse blocks on the Commodore, a main and engine compartment block.

The main block is located behind the drop down cover directly below your steering wheel, this cover can be dropped by turning each of the plastic inserts 45 degrees with a 10c coin or similar. The engine compartment block is obviously located in the engine compartment and can be found on the driver's side near the battery. This block contains most of the relays as well as the fusible links.

Each fuse is made to protect a specific circuit, and the various circuits are listed on the fuse panel itself. On more than one occasion I have witnessed someone in a VN stranded at a service station. Only to be saved by a mechanic who walks out and replaces the 10A ignition fuse. The humble fuse is something that should never be overlooked.

If an electrical component fails you should always check the fuse first, under normal operating conditions a blown fuse is the most common reason for component failure. How do I know if a fuse is faulty? I hear you ask. Spotting a blown fuse is really quite easy. With the suspect fuse in your hand, examine the clear plastic body; if the wire inside has a small black mark, gap or break you have a blown fuse. However, sometimes a faulty fuse is not as easily spotted and you may need to do a continuity check.

To check for continuity simply place a multi meter between the 2 feet of the fuse and select the ohms scale. An operational fuse should have a reading of 0 ohms, indicating no resistance. Fuses with resistance must be renewed.

When renewing a fuse it is good practice to replace it with one of identical rating. For example, if a 20Amp fuse is blown you simply replace it with a 20Amp fuse, nothing more or less. Fitting a fuse with a rating higher or lower than factory specification is not recommended, as each circuit needs a certain amount of protection. If you go lower the fuse will blow too easily, this is referred to as “nuisance blowing”. On the other hand if you go higher it just won't blow, providing no protection at all.

Please Note- If a fuse is renewed correctly and immediately fails you have an electrical fault. Do not renew the fuse again until the cause of the problem has been rectified. A short circuit in the wiring caused by broken or deteriorated wire is the most common problem.