2003 sl500 battery isolator relay location

#2003 sl500 battery isolator relay location manual

But always check all other possible causes first. In some rare cases, there might actually be a faulty engine control unit. In some rare cases, there might be a problem with the engine control module not controlling the alternator’s charging.Ĭheck for any trouble codes with an OBD2 scanner to determine if anything is any other damaged part that prevents it from charging. In this regard, the engine control unit (ECU) controls most of the car’s electrical components. Engine control module errorĬars are increasingly coming with modern electronics. In theory a car can run only with the alternator charge, but this can cause heavy voltage spikes and other strange symptoms so this means that a bad car battery can cause an alternator to not charge also. A really bad car battery might actually not take care of the charge from the alternator, which will cause the alternator not to charge at all. The alternator and the car’s battery work hand in hand. To measure this properly, you need a wiring diagram of your specific car model. If you have a 3rd one, it does often go to the engine control unit. You should usually have 12 volts on one of these wires, and the other one goes to the battery light on the dashboard. Remember that measuring them is not always correct because you have to load test wires that are half broken or have a bad connection. You can usually find that the cable will get warm if there is a bad connection somewhere.Ĭheck or measure these wires with a multimeter. You will find one big main cable together with two or three small ones.Īll these wires are important for the alternator’s function, and if one breaks off – you might lose the charging function.Ĭheck the big power cable connectors between the alternator and the car battery to ensure there is no corrosion there. Wiring issues or connectorsĪn alternator does usually has 3 or 4 wires to it to function properly. In some cars, you might also find another small fuse to the alternator’s control-usually a 15A to 20A fuse.

#2003 sl500 battery isolator relay location manual

The solution is to check your car’s manual for the particular fuse that controls the alternator and replace it. When this happens, the current will stop flowing from the alternator. It is often an 80A fuse or more and is most often found in your car’s fuse box in the engine bay.įuses blow up due to a power surge, or they wear out. There is often a huge fuse connected to the alternator’s big power cable. The serpentine belt and pulleys are often pretty easy and cheap to replace. Some older cars have manual tensioners, and in this case, you might have to tighten the serpentine belt. Most cars have automatic tensioners, but these can fail, so it is better to double-check. This can also happen if the serpentine belt is not tightened correctly. The serpentine belt powers the alternator, and if it fails, the alternator will stop working the moment your belt wears out and breaks, or the pulley becomes damaged. Broken Serpentine beltĪ closer observation of the alternator will reveal a pulley and belt system that works to convert mechanical energy into electrical energy. If you have already replaced it with a brand new alternator, but it’s still not charging the battery, you should keep reading in this list. Nowadays, alternators are quite cheap, and mostly it is more worth replacing the whole alternator. It was more common to replace parts inside the alternator like the carbon brushes, diode plate, or voltage regulator on older cars. You might need some knowledge about alternators to replace these in most cases. Sometimes there is an electrical problem in the alternator, and even if the voltage does not change, it might be damaged.Īnother common cause is a bad diode plate or a voltage regulator. If the voltage change and go back to normal when you tap it lightly with a hammer while the car is running – the Carbon brushes are worn out and needs to be replaced in the alternator, or the whole alternator. You can carefully tap it with a hammer while the car engine is running while checking it with a multimeter on the car battery to see if the voltage is changing. The most common reason why your car is not charging the battery is actually because of a worn-out or damaged alternator. Worn out carbon brushes or damaged alternator Diagnosing an alternator that won’t charge Causes of Alternator Not Charging 1.