What are the symptoms of a bad alternator in a GMC Sierra?
Here are the most common symptoms of a bad alternator in a GMC Sierra: The battery light is designed to tell you that there is not enough voltage to properly charge the battery, or that the battery itself is not holding the proper voltage. In rare occasions the service engine soon light may light up.
Why does the battery warning light come on after replacing the alternator?
A relatively common “side-effect” of replacing a battery and/or alternator in a car is to have the voltage (battery) warning light come on. This is especially true in late-model vehicles with their more sophisticated internal diagnostic systems.
Is the battery light on the 2nd Gen Tacoma?
Battery light is on. Alternator and battery tested good?! Discussion in ‘ 2nd Gen. Tacomas (2005-2015) ‘ started by Jchavez, May 11, 2013 . So a last week my battery light popped on. After 5 minutes of driving it will go on and won’t turn off. I had my alternator and battery tested 3 times and they tested good every time. Any ideas?
Is the control wire on my alternator broken?
As to the OP, there have been a couple members who have had problems with the control wire connector. This is the small connector that plugs into the back of the alternator. Check to make sure the wire is not broken.
Here are the most common symptoms of a bad alternator in a GMC Sierra: The battery light is designed to tell you that there is not enough voltage to properly charge the battery, or that the battery itself is not holding the proper voltage. In rare occasions the service engine soon light may light up.
What to do if your alternator is over charging the battery?
Ask an assistant to start the engine and hold engine speed at about 1500 RPM. Measure voltage across the battery with your DMM. You should get 0.5 to 2 volts higher than base voltage. If you are getting more than 2 volts above base voltage, most likely your alternator is over-charging the battery or the battery is faulty.
What causes an alternator to output low volts?
If the voltage at the battery and alternator don’t match. For example the battery reads 12v and alternator reads 14v. This means that there is an issue with wiring. While applying the same conditions as above.
What causes an alternator to get really hot?
High voltage, bad diode, improper alt fan, bad bearing , defective heat sink ,high voltage drop accross alt power wire or ground wire . A few places to check alternator fan, now why didn’t I think of that?
Can a bad alternator leave a GMC Sierra without power?
A bad alternator can leave your GMC Sierra without power and unable to move. Alternators don’t always go bad in the exact same way. We’ll cover the symptoms of when an alternator goes bad, and how to diagnose a bad one (which is really pretty easy).
Is it possible for an alternator to overheat?
Yes alternators give off heat, they have an internal fan to cool it. The will get too hot to touch after running a while. I would test the voltage at the battery with a meter, should be around 12 V. A good test is at 1500 rpm, headlights, heater fan and radio on, should hold around 14 V.
What are the symptoms of a bad alternator?
Outside of the battery warning light, a dead battery is the most common symptom of a bad alternator. As the alternator can no longer supply your Sierra with an adequate power supply, it will begin to feed off of the reserve in the battery.
Is the alternator on my Chevy Malibu overheating?
Automotive Forums .com Car Chat > Chevrolet > Malibu > Overheating Alternator??? Overheating Alternator??? After running fine for 15-20 minutes my alternator will begin to heat up until the point where it is too hot to even touch.
Can a Saab 92 start with a bad alternator?
Dual ignition coils (the blue cylinders at the top of the picture) on a Saab 92. Before you go out and order a new battery or alternator, test some of these different systems. If your alternator, coil, battery, or starter is bad, the car probably won’t start, and it definitely won’t be drivable.
When to replace the alternator in a Chevy Trailblazer?
With the engine just fired up, you should get over 14.2 volts. If you got 14.2 or more volts, the alternator is charging fine. If it’s still showing in the 12’s, it’s time to replace the alternator. If it’s producing a voltage level in the 13’s, go ahead and take it into a parts store and have it tested. It’s probably bad.
How to diagnose an alternator or electrical problem?
Diagnosing alternator problems can be a bit tricky because the electrical system in a car comes from two places, the battery and the alternator. I’ll give you a little background so you can understand what both systems do. The battery has one primary function, which is to start the car.
What should I do if my alternator keeps dying?
The alternator is essentially a generator and it keeps your battery charged while supplying additional electrical power for the other systems in the vehicle. If you have a new alternator and your battery keeps dying on you, then there’s definitely a problem that you’re going to need to look into.
Can a car battery be drained by an alternator?
While you might initially think that any problems with electrical things like lights or radio not working are directly related to the battery, the alternator is actually where most of the power in your vehicle comes from. Consider that if you were to leave the lights of your car on overnight by the next day your battery might be drained completely.
With the engine just fired up, you should get over 14.2 volts. If you got 14.2 or more volts, the alternator is charging fine. If it’s still showing in the 12’s, it’s time to replace the alternator. If it’s producing a voltage level in the 13’s, go ahead and take it into a parts store and have it tested. It’s probably bad.
What do I need to know about my GMC battery?
WHAT IF I’M NOT SURE IT’S MY BATTERY? Your GMC Certified Service experts can give you a no-charge battery test to determine if your battery needs replacing or if there is an issue with another charging component.
What’s the connection between the battery and alt light?
So it only has an output to battery (BAT) wire, and a LAMP (L) wire to tell the PCM to light the ALT light. In this setup, the regulator always reads internal voltage to determine charging rate.
What kind of wiring does a GM alternator use?
The PDF shown here is for a GM CS 130 and CS 144 alternator. Both of these alternators (generators) can be wired differently depending on their application. They can have a BAT wire and two additional wires, or a BAT and a single “L” wire.
How to change the battery on a GMC Sierra?
Install the battery cable (positive), remove the large alternator wire. Remove the the small positive wire that comes off the battery and goes to the fuse block. Remove it at the fuse block and put your meter inbetween the fuse block and that small wire from the battery.
WHAT IF I’M NOT SURE IT’S MY BATTERY? Your GMC Certified Service experts can give you a no-charge battery test to determine if your battery needs replacing or if there is an issue with another charging component.
What should battery voltage be on GM Truck?
It appears the needle fluctuates between 12 and 15 or volts. The battery gauges on most vehicles I have owned stays around 13 to 14 volts and doesn’t move much unless something that consumes a lot of power is turned on. Mine does this with nothing additional running on the truck other than the radio and a/c.
Why does my GMC Sierra 1500 HD battery drain?
ASE MASTER replied 11 years ago If the draw is at the fuse block, then try removing the fuse block and disconnecting the connectors under the fuse 1 at a time. It has to stop with one of these connectors. Makes no sense to have a draw thru the fuse block but not comming out. The fuse block is made to come off so this should not be hard.
What kind of battery does Silverado Sierra 6.6L have?
I have a 2007 new body style Sivderado HD 2500 6.6L diesel with dual batteries a Bosch alternator and only 40k miles. The problem I’m having is it takes over 3 minutes from a cold start for my voltmeter to move from the 12 volts mark.
What to do if your alternator is not charging?
Alternator Fuse Check this first, if new alternator is not charging. Shown on GMC Yukon Tahoe Sierra – YouTube If playback doesn’t begin shortly, try restarting your device.
What kind of alternator does a Chevy Silverado use?
These trucks do not use traditional/old school alternator with voltage sensing charging systems. As much info as the ECM must have to do what is described, it seems likely that a fault in either alternator would result in a message. This is a little of GM’s info on this system as presented in the upfitter guides:
Alternator Fuse Check this first, if new alternator is not charging. Shown on GMC Yukon Tahoe Sierra – YouTube If playback doesn’t begin shortly, try restarting your device.
How does a battery charger work on a Silverado?
AC voltage is then sent through a series of diodes for rectification. The rectified voltage has been converted into a direct current (DC) for use by the vehicles electrical system to maintain electrical loads and the battery charge. The voltage regulator integral to the generator controls the output of the generator. It is not serviceable.
How is the alternator connected to the ECM?
Once the engine is running, the regulator varies the field current by controlling the pulse width. This regulates the generator output voltage for proper battery charging and electrical system operation. The generator field duty terminal is connected internally to the voltage regulator and externally to the ECM.