VAUXHALL ALTERNATOR

Difficulty:

Vauxhall Vectra Alternator

Since its introduction in 1995 the Vauxhall Vectra has proved by and large to be most dependable, but as with all vehicles some parts and systems can eventually give trouble and the Vauxhall Vectra alternator is one of them.

Sluggish starting and/or the red ignition warning light staying on after the engine has started can herald the failure of the Vauxhall Vectra alternator and the need to purchase Vauxhall parts. Before leaping to the telephone and sourcing a new or used alternator a few simple checks can save you time and trouble.

Raise the bonnet and check that the auxiliary belt driving the Vauxhall Vectra alternator is complete and has the correct degree of tension, NB only carry out these checks with the engine off. If these are found to be OK move across to the battery, checking the security of both connections including all cables. The next part of diagnosis involves the use of a basic multimeter, I say basic because you can purchase such an item that will suffice most auto electrical testing for less than £20.00. With the engine running check the voltage reading measured between the battery terminals (red/positive and black/negative) this should be between 13.5 and 14.5 volts DC (direct current), if the reading is lower than this move the negative (black) meter probe to a good clean metal point on the engine, if the meter reading rises then check all earth cables between the engine and the battery negative. Should this not be the case move to the Vauxhall Vectra alternator and check the connections around the alternator itself, NB, the Vauxhall Vectra alternator is mounted at the right hand rear of the engine and should only be investigated with the engine switched off.

Care must be exercised when dealing with vehicle electrics as the opportunity for short circuits caused by the mis-handling of hand tools is very real and can be both painful and expensive. Due to the position of the Vauxhall Vectra alternator access to the rear terminals whilst the engine is running is very risky and should only be attempted by the experienced professional.

Removal of the unit for specialist bench testing is relatively straight forward if a little fiddly. Prior to any disassembly of the start/charge system the battery must be disconnected to prevent short circuits, before carrying out this procedure ensure that you have any radio security codes as these will almost certainly be required when the battery is reconnected.

Particular points to mention are the Vauxhall Vectra alternator top and bottom mounting brackets, the bolt on connections to the unit itself and the wiring/connections to ancillary engine components, for example crankshaft sensor, temperature sensor etc.

Modern alternators such as those fitted to the Vauxhall Vectra are virtually a sealed unit with limited scope for DIY disassembly and repair. However, it is always worth inspecting the unit externally, looking particularly for physical damage (mechanical) or signs of short circuits (electrical), a common fault, not just on the Vauxhall Vectra alternator is a poor connection at the output terminal, this is apparent by discolouration of the terminals caused by high resistance. Prior to fitting a replacement new or used unit all connecting surfaces must be restored by wire brush or abrasive paper if this does not produce a good clean contact the connector and associated wiring must be repaired/replaced.

Fitting the replacement unit is of course the reverse of removal and the addition of a drop of oil on each thread will aid the refitting of nuts/bolts and allow accurate tightening.

Whether you opt for new, reconditioned or used Vauxhall Vectra alternator it is vital that you charge the vehicle battery prior reconnection as the sudden demand for a high charge from the alternator can cause it to fail very quickly. This situation can almost certainly wreck any warranty supplied with the unit.

On reconnecting the battery start the engine and check the correct alignment of the drive belt as it runs across all the drive/driven pulleys, this is most important as it is very easy to fit a modern multi-vee belt one groove out causing premature belt failure, once done reconnect the multimeter and check the charge voltage across the terminals, ensuring that the readings fall within the specifications previously mentioned. The voltage should also be checked with the system under load (headlights, blower, heated rear screen etc switched on) and with a raised engine speed (2000rmp approx). Should any fault still be apparent in the Vauxhall Vectra alternator circuits it is well worth while seeking professional advice.

For the complete guide to replacing an alternator, visit www.haynes.co.uk