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This is a commercial vehicle 2000 peterbilt i want to know how i can check the alternator to see if it needs to be replaced?
Wiki User
∙ 15y ago
You will need a voltmeter,or the volt gauge in the dash, if it has readable numbers on it.(test is more accurate with a voltmeter)With a volt meter,hook up positive to positive and negative to negative,right at the batteries will suffice.Make sure the meter is set to D.C. in the range of approximately 20 volts.With the truck running at idle, batteries charged,and all accessories turned off you should have about 14 volts give or take .5 (1/2) a volt,will vary depending on the charge in the batteries.If you are only showing 12 volts or less the alternator is not charging or(you have a bad connection,bad battery or a short somewhere).If it is between 12 volts and 13.5 either the batteries are not fully charged,the alternator is not charging properly or you may have a bad battery or bad connection.If the batteries charge okay with a portable charger it is not always safe to assume that they are in good condition.If you suspect a bad battery have them load tested especialy if they are over 3 years old. (It is important that all connections are clean especially the battery posts and connectors)Also if an alternator has a bad diode,it can still charge but can drain your batteries down when the truck is shut off.
Wiki User
∙ 15y ago
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How do you change the alternator on a 99 Deville?
The alternator must be removed and replaced from the bottom, as with raising the vehicle high enough to work from underneath "safely".
Why is your alternator overcharging after you replaced it and it ran fine for a week?
It is probably a bad voltage regulator. Sometimes they are located in the alternator and can go bad in a new one. On Ford vehicle the voltage regulator is separate from the alternator.
Alternator keeps going bad?
There are a few reasons why your alternator might keep going bad such as rusty latches under the car. You may also have leaks, dents, or parts that need to be replaced on the vehicle that are effecting your alternator.
Alternator is over charging how do you fix it?
It depends on the year of the vehicle. Newer (late 60s/early 70s on) had "internal regulator alternators", so the alternator needs to be replaced. Older cars have a regulator, usually mounted on a fender well, the fire wall, or the radiator support which canb be replaced independently of the alternator.
What type of vehicle is the 359 Peterbilt?
The 359 Peterbilt was a long-nosed truck which was specialized as a wrecker. Peterbilt generally produces both medium and heavy-duty trucks and was founded in 1939.
Why does your alternator light come on randomly and intermittently?
If an alternator light keeps coming off and on, this may indicate that the voltage output of the vehicle is going up and down intermittently. This may mean the alternator may need to be replaced soon.
What is a brush and how many of them are there in an alternator of a motor vehicle?
What is a brush and how many of them are there in a alternator of a motor vehicle?
What does the alternator do for your vehicle?
the work of an alternator is to charge up the battery while the vehicle is in motion
Is a mercury mariner a non-commercial vehicle?
The Mercury Mariner is a passenger vehicle. It's only a commercial vehicle if used for commercial purposes. If it has passenger plates, it is not considered a commercial vehicle, and is not subject to commercial vehicle restrictions.
Why is the alternator regulated?
An alternator is regulated to prevent overcharging of the vehicle's battery.
How do you replace a thermostat on a 2004 envoy?
If your vehicle is equipped with the 4.2ltr 6 cylinder, the thermostat and housing are replaced together, located on the side of engine block behind alternator.
First start very slow draging alternator?
Either have the Alternator rebuilt or replaced. A bit cheaper to have rebuilt however this is determined by Make, Model and Year of Vehicle. The reason it is dragging is the bearings are worn out and the unit can very easily SEIZE.
