Charging problem I wonder if you can give me the output readings from the alternator as I wish to resolve a charging problem. Obvious solution would lie at the voltage regulator, but at £80 I wish to rule out the alternator first.

Could only be wiring, voltage regulator, or the alternator itself.
Most alternator's have replaceable brushes wish wear out over time, a bit involved but not too difficult. Have a cheap voltmeter on hand and work your way back looking for bad wires.
This is the time a couple bucks spent for a service manual from say amazon for example, will give you simple step by step instructions,, the manual will save you so much frustration you wonder how you ever got by with out it.

amps reading on the truck amp meter is the current that is being generated to run everything as well as charge a battery that will be at best around 80% charged.bench testing an alternator gives these readings as the regulator is feeding into fully charged batteries with no draw on the system. When batteries are 100% charged the charge rate will be as low as 2 amps but in a car where there is a current draw for the ECM , ignition , fuel pump and what ever the alternator feeds these first before it charges a battery. You used a amp meter to get a voltage reading which is reading the voltage drop across the current draw. If you had used a voltmeter (multimeter) then you would see a voltage increase with the rpm increase. The

Hello and good morning. Couple of things going on. First, alternator isn't charging, or is it.
Lets check the alternating output (battery positive and negative post). Take a cheap voltage meter and set it for DC volts around 20 volts on the scale. Place the test leads across the battery while the engine is running. The voltage across the battery terminals should be 13.8 DC volts to 14.1 DC volts. If you are getting this reading in volts from the multi-meter then you vehicle is charging correctly.



Next, check to see if there is a ground wire on the alternate it just a breaded copper cable the is hook to the case of the alternator to the engine block. If there is a ground cable, then that is OK.



Now, let check the tension of the alternator serpentine belt, it need to tight but extremely tight. Also check the condition of the belt. If it has cracks along the inter ridges of this serpentine belt then it needs to be replaced.



Any of the three things mentioned above can and will give problem to your vehicle. Also, any combination of the three above. Wish you luck. GB...stewbison

Battery light is directly connected to the voltage regulator of the alternator. If it is on, it means you have a bad alternator/regulator combination meaning a new alternator is in order.

This is a very common problem. That's why they have a light for it.

Wish you luck on this one.

You shouldn't check the amps - they vary according to the status of the battery, you should check the voltage and 13.6 V is way too low - the battery is practically never charged and this is why it fails just by sitting.
Check the alternator and replace it if in doubt.

No, if the light is coming on it indicates that the alternator output is not adequate to recharge the battery. You have some sort of charging issue. Take the car to an autoparts store and have the alternator output checked. Most stores offer this service free of charge. You may have a short in the output wiring or some other problem. Hope this helped and best wishes.

Since you just replaced the battery and alternator, I would take the car to a parts store and have them check the alternator output. See if there is any fluctuation in the output. I had a short once in one of the wires in the plug that was causing an intermittent charging problem. I found it by moving the wires around while checking the alternator output. I re-soldered the wire into the plug and eliminated the problem. Hope this helped and best wishes.

put the meter in series remove wire gointo back of alternator put one lead on wire and one on alternator that should give you your reading

a bad battery shouldn't give you low ammeter readings if you jump the vehicle and it stays running the alt is probably working if you have a meter to test it there should be 14-14 1/2 give or take if it is charging