My 1994 vw gulf is not charging properly alternator check out ok but i am only getting 12 v while the vehicle is running

Check the alternator belt tension it ok . Then With the engine running at a fast idle check the voltage at the battery terminals , 14 to 15 volts ok . 12 volts or below the alternator or voltage regulator is at fault.

You need an auto electrician to check out your vehicle's electrics.

Go to Autozone,they will check your battery and alternator for free,takes just a few minutes.

ok i,m going to assume that you are talking about the battery based on the information

the first thing i would check is the alternator to see if it is functioning properly if not you will have to replace the alternator also check all the all the leads leading to the alternator

good luck

Take a battery that has a good charge on it or 12 volts put it in and start it then take a multimeter and put the red lead on to the power lead on the back of the alternator and ground the black lead.It should read between 13-14.5 volts anything more or less replace alternator.If alternator checks out ok check battery voltage after charging it.Must have at least 12-12.6 volts anything less replace battery.

Hello Mdeon.

The red light is indicating that the alternator is not correctly charging or not charging at all.
Basic check would be to verify that the drive belt is actually turning the alternator. A loose belt can do this.
If the belt is OK, then check the connections at the alternator for looseness or corrosion.
Check the main terminal at the alternator for 12.5 volts ignition key off.
Make sure the mounting bolts for the alternator are clean and tight.
If all that checks out, replace the alternator, it is defective.

Thank you for using FixYa.

KL

you take the vehicle to an accredited auto electrician and have them check the charge circuit and battery
could be the alternator or voltage regulator or problem battery
have them check the drive belt condition and tension
if the units have been rebuilt by reputable electrical company, they are a cheaper alternative to brand new and should have a 6 months or 12 month warranty with them

If you havent replaced the battery I would start there. If the battery has a dead cell in it then it will effectively remove the charge that your alternator is putting out causing your vehicle to stop running because it has no power. I would jump start the car without the battery hook up and remove the cables and see if it runs that way. If it does you have a bad battery.

It sounds like the battery has gone dead and will need to be replaced due to a bad Alternator. Once you get the car started, check the voltage on the battery, there should be 13.5 to 14.5 Volts. A fully charges battery should have 12 volts with the engine not running and once the engine is running there should be 13.5 Volts with the head lights on and heater on too. If there is less then 12 volts reading on the battery with the engine running, then replace the Alternator. You can pick up a Alternator at Auto Zone and they can give you the step by step instructions to replacing it with common tools and they can also check the Alternator in your car to before you buy the new one. Good luck and hope this helps and insect the wire harness from the battery to the Alternator, look for any sighs of damaged like corrosion and repair any damages to the wire harness.

Have you been having trouble starting it? A real easy way would be to attach a multimeter,( DC voltmeter) and check voltage before and after engine is running. Should get 12-12.5 volts not running, and 12.8- 14.5 roughly when running, depending on how much charge battery needs at the time, which is regulated in the alternator.
If battery is lower than 12 volts, you may want to have it tested to determine it's condition.