Continued from last week.

OK, I have left the Battery, Alternator, generator light for last. That is because this ONE light causes more people to WATE money, than any of the warning lights. These lights are identified differently in different vehicles. Some vehicles show them as the "BATTERY", "ALTERNATOR", "GENERATOR", or "CHARGING" light. This is where the confusion starts.

After all, if your vehicle is equipped with a RED light that is called the "BATTERY" light, it is only normal to think that there is something wrong with the battery. This stays true for ALTERNATOR lights, (Suggesting a alternator problem.) GENERATOR, (One of my personal favorites because vehicles have not used GENERATORS for about 40 years.) "BUT", what the light is REALLY telling you is that there IS a problem with the vehicles charging system. Something has happened that is PREVENTING the vehicles Battery from being RECHARGED. This light DOES NOT MEAN that there is a problem with the battery. I don't even want to guess at how many people I have heard from that have seen a Battery or Alternator light come on and go and buy a Battery or Alternator. (Only to find out that the light is STILL on.) I am going to try to be as brief as possible, but if the Battery or Alternator light comes on, DOES NOT MEAN THAT THERE IS A PROBLEM WITH THE BATTERY OR THE ALTERNATOR.

All that it means is that the charging system is not working properly and some testing is going to be required in order to diagnose the system properly.
1. If the battery is not being charged and a person just takes the battery in to be tested, THE BATTERY WILL FAIL. (But, there may NOT be anything wrong with the battery. A battery MUST be as fully charged as it can be before it is tested or it will show as faulty. In fact, a Battery SHOULD be charged for 12-24hrs BEFORE it is tested.)
2. An alternator NEEDS a good battery in order to be able to produce a charging voltage. (If a Battery is very low, an Alternator WILL NOT work.)

In case some of you missed it, I got into a real DEAL on this posting because I tried to SAVE a fellow some money. Now I will try and explain how this all works. You have a vehicle that has a Battery and a Charging device used to try and keep the battery fully charged. The Battery has acid in it and when it is properly charged the strength of the acid is measured by a measurement called, "Specific Gravity". If the Battery is LOW in charge, the specific gravity of the acid will ALSO be low. (AND, a battery MUST have a certain specific gravity reading BEFORE it can be PROPERLY TESTED.) So, if the battery has not been getting a PROPER re-charging voltage and it is tested, it WILL FAIL the test. But, putting in a NEW battery will NOT fix the problem. Also, if a battery is not producing enough voltage, the alternator will NOT charge and the alternator will test as having a LOW output. (But this does NOT mean that the Alternator is not working properly.) A BAD battery WILL NOT allow for a proper Alternator test and a Alternator that has NOT been charging a battery, will NOT allow a battery to be tested properly. If the red warning light for the charging system comes on, there are some very basic tests that MUST be done and you should ALWAYS start with the Battery. Have the battery FULLY charged and tested. (Remember it will take 12-24hours to charge.) After the Battery has been fully charged and tested, THEN HAVE THE ALTERNATOR CHECKED. (The Alternator should be able to produce 75% of it's Maximum rating or it has a problem.)

However, there are a number of wires and circuits that can show an Alternator as not charging when IN FACT, there is NOTHING wrong with the Alternator. I know this sounds like a lot of MUMBO-JUMBO, but that is the way the system works and a person MUST be able to understand the basics BEFORE they start buying stuff and WASTING MONEY. In short, if the Battery HAS NOT been getting charged by the Alternator, it will test as a BAD battery. (Even though there is NOTHING WRONG WITH IT EXCEPT IT IS LOW IN CHARGE.) If the Alternator DOES NOT have a good battery to FEED it, it will NOT test as a good Alternator. But, BOTH can be replaced and the red warning light will still be on. Is it as clear as MUD???????? (Oh I know, anybody can fix a vehicle.)

"TOOT" Rick "The Wrench" - July 4th,1999
Copyright of Rick The Wrench, 1999