RAC Approved Repair and Go Garage

FAQ’s

The very first indication that your alternator is not working is that your battery will go flat. Secondly you’re warning light on your dashboard will either not illuminate or will continuously glow while the engine is running. The best test to see if your alternator is working is to use a voltmeter. This should be connected across the positive terminal from the back of the alternator output lead (B+) and negative (B-) terminal on your battery. If you can not get to the positive terminal on the back of your alternator you can use the positive terminal (B+) on your battery. (This is not a sure safe way as there could be a voltage drop between the battery and your alternator). Your alternator should charge between 13.6 volts and 14.3 volts when idling, once your vehicle is running and you put on your accessories such as lights, wipers, heater etc, the voltage may drop to around 12.4 volts this is acceptable. If you get readings outside of these guidelines then your alternator is not functioning correctly, and should be taken to an Auto Electrical specialist who will diagnose the fault for you.

A battery is needed to power the operating system of your vehicle. Once the vehicle is running the battery is charged by the alternator which is driven by the engine. While in operation the alternator creates electricity, normally about 13.6 to 14.3 volts, and recharges the battery until it is fully charged. Some later vehicles control the vehicles voltage from the engine control unit (ECU), causing the alternator to charge higher around 17.1 volts at low rpm as your vehicle needs this high output from the sudden use of heaters, wipers etc when the engine is first started. The alternator is one of the hardest working electrical components in your vehicle; this is because when your vehicle is running the alternator is always running! It has a very busy job charging to provide the engine and the vehicles accessories with the power it requires. An alternator is a very complex part consisting of many different components such as rotor, stator, regulator, diodes, brushes, bearings, pulley wheel and some times a vacuum pump for diesel applications.

Yes it can charge in both directions, either clockwise or anticlockwise. The only thing you have to be careful of is that the cooling fan blades are facing the correct way, to cool the alternator down once rotating, if they are not the alternator will overheat and cause damage to its internal components. A dynamo on the other hand is directional and will only charge one way, a directional arrow is normally found on the body of the dynamo to show its rotation.

A very easy and quick test is to turn your ignition key to the first stage, put your head lights on to full. If your head lights are bright then your battery has plenty of charge in it and it is ok. If your head lights are dim your battery is low in charge and needs to be checked or replaced. Continue with the test while your head lights are on with a full battery and turn your ignition key to the starting stage, if your head lights stay bright while the starter is turning slow then the starter motor needs to be checked or replaced, if your headlights dramatically dim while the starter is turning then your battery needs to be put on a full load test.

We can either arrange a collection from yourselves from our own van delivery service for free (within a designated area) or for collections outside of the designated area we can arrange for our carriers to collect the part and send it to us for reconditioning at a cost of £15.00. Alternatively you can send us your old unit or come direct in person. Once your part has been reconditioned we will arrange for delivery or collection depending on your requirements.

Very simple just put your old unit in its original packaging, contact us and we will collect it for free and no extra charge. We will arrange for the collection of it/them either by our own delivery vans or via our carriers.

Not a problem return the part to us complete with details of your purchase and we will issue a refund or credit less a restocking/handling charge of 20%. We cannot accept goods for refund or credit if returned more than one year from date of invoice.