Rick's Free Auto Repair Advice » Battery

Alternator testing

Rick — Fri, 23 Apr 2010 22:09:17 +0000

Cardone, a major re builder of alternators has issued a service bulletin regarding the right and wrong ways to test an alternator.

THE WRONG WAY

Disconnecting the battery cables while the vehicle is running can generate a voltage spike as high as 150 volts! That’s enough to fry every computer in your vehicle, along with your stereo, fuses, remote door locks, etc. Reconnecting battery cables generates a second spike.

THE RIGHT WAY

The battery must be fully charged and a volt meter must read at least 12.6 volts with the engine off and no loads (headlights off, etc). Next, start the vehicle and apply the voltmeter. It should read between 13 and 15 volts. Be aware that newer vehicles DO NOT CHARGE the battery unless it needs charging!!

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Voltmeter fluctuates on GM Trucks

Rick — Mon, 12 Oct 2009 05:31:38 +0000

GM has issued a technical service bulletin #07-06-03-009 advising dealers that fluctuating voltage on the vehicle's voltmeter is NORMAL and is not a reason to replace any parts. The TSB applies to 2005-08 Cadillac Escalade, 2005-08 avlanche, Silverado, Silverado Classic, Suburban, Tahoe, 2005-08 GMC Sierra, Sierra Classic, and Yukon.

The charging systems in these vehicles do not use an alternator decoupler to increase gas mileage. Instead they incorporate a Regulated Voltage Control (RVC) system. The RVC is controlled by the PCM and adjusts the amount of "field" to the generator. The purpose of the RVC system is to eliminate charging when it is not needed in order to improve fuel economy.

The targeted voltage in these system ranges from 12.6-13.1 volts when the system is in "Fuel Economy Mode." As soon as the PCM detects that the system needs additional power generation, it exist this mode and moves into "Charge Mode" at normal charging rates. So the vehicle owner may notice a fluctuation in the voltage meter from 12 to 14 volts. This is NORMAL. Do NOT replace any charging system components.

Some of these vehicles have a "tow/haul feature." When this feature is enabled, the charging system bypasses the economy mode and the generator output should be in the 13.9 to 15.5 volts range, depending on the stat of charge of the battery and the battery temperature.

You can force the system into Charge Mode by switch into the tow/haul mode, OR
simply turn on the vehicle's headlights. That will increase the generator's output to 13.9 to 15.5 volts.

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Hover your mouse over the REPAIR ARTICLES tab at the top of the page. The click on DIAGNOSTICS to search by SYMPTOM, TROUBLE CODE, or read TECH TIPS on how to diagnose a problem

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Click on REPAIR TOPICS to read individual articles written for specific automotive systems

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Here are some quick links to speed up your research

Click on the link below for speedy navigation:

ABS issues, how to bleed ABS brakes

Airbag issues or SRS light on

Alternator issues or how to test

Belt diagram or serpentine belt issues

Blower motor

Blower motor resistor

Brakes, brake issues, what kind of brake parts to buy, ABS issues

Car Alarms or Antitheft systems

Cooling system, Water pump, What type of coolant to use

Engine flush

Firing order, cylinder layout, finding #1 cylinder

MAF or MAP sensor

Oxygen sensors, How they work, How to change, How to test

PassLock or Passkey

Thermostat issues

Transmission flush

Serpentine belt diagrams

Window issues, power window motor, replace window regulator, glass adhesive

Speedometer needle on wrong side of peg – Caravan

Rick — Fri, 04 Sep 2009 01:03:22 +0000

Drivers may find that the speedometer needle is on the wrong side of the stop peg after charging or changing the battery or cleaning the battery terminals.

You do NOT need to remove the instrument cluster to fix this problem.

Insert the key in the ignition. Then press and hold the trip odometer reset button until you see "Sof" appear along with a software version number (like Sof 3.2). The cluster will then display any trouble codes and when it's done, the word "end" will appear. The cluster will then initiate a series of tests than include sweeping the needles side to side. When the testing is done, the needle will be on the correct side of the peg.

Alldatadiy.com

eautorepair.net

Both Alldata and Eautorepair offer professional grade shop manuals at a price you can afford. Check them out!.

Hover your mouse over the REPAIR ARTICLES tab at the top of the page. The click on DIAGNOSTICS to search by SYMPTOM, TROUBLE CODE, or read TECH TIPS on how to diagnose a problem

Click on MAKE an MODEL to see all the articles I've written for your vehicle
Click on REPAIR TOPICS to read individual articles written for specific automotive systems

If you've had your car scanned and know the trouble code go to TROUBLE CODES

Here are some quick links to speed up your research

Click on the link below for speedy navigation:

ABS issues, how to bleed ABS brakes

Airbag issues or SRS light on

Alternator issues or how to test

Belt diagram or serpentine belt issues

Blower motor

Blower motor resistor

Brakes, brake issues, what kind of brake parts to buy, ABS issues

Car Alarms or Antitheft systems

Cooling system, Water pump, What type of coolant to use

Engine flush

Firing order, cylinder layout, finding #1 cylinder

MAF or MAP sensor

Oxygen sensors, How they work, How to change, How to test

PassLock or Passkey

Thermostat issues

Transmission flush

Serpentine belt diagrams

Window issues, power window motor, replace window regulator, glass adhesive

Rick — Fri, 21 Aug 2009 15:41:00 +0000

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Battery Drain Testing on Ford Vehicles

Rick — Wed, 25 Jun 2008 02:05:00 +0000

If you’ve suffered a dead battery and both the battery and charging systems check out, it’s time to perform a parasitic drain test. The test involves hooking an ammeter in series with the negative battery cable to measure the amperage draw. Professional technicians use a clamp on ammeter.

Here’s what you’re looking for: Most computers have a keep alive mode that keeps drawing current for about 15 minutes after shutdown. But if you’ve got a Ford vehicle, give it a good hour for all the modules to “go to sleep.” That means shut down the engine, hook up your meter, close the doors, make sure all the lights are off and walk away for an hour. Do NOT touch anything! Don’t open doors. Don’t turn on lights! That will wake up the computers. If you don’t follow this advice, it’s not uncommon to see current readings in the 200 milliamp to 1.2 amp range. That’s WAY above normal and it will trick you into suspecting current draws that are perfectly normal – for a computer that’s awake.

Acceptable current draw in sleep mode is anything UNDER 50 milliamps. If your reading are higher than that after an hour, you’ve got a module that either hasn’t gone to sleep or is sticking. Here comes the fun part. You have to pull fuses one at a time until you see the current drop. That will narrow down the troublesome circuit. But how do you do that without opening a door and waking up a computer? (normally you’d mechanically depress the pin switch in the door pillar—but Ford doesn’t use those anymore. The door switch is inside the door attached to the latch mechanism) There are only two ways: 1) hotwire the driver’s door switch so the computer thinks it’s closed. 2) Crawl in through the driver’s window.

Are you having fun yet? Do you really think Ford has a better idea?

Alldatadiy.com

eautorepair.net

Both Alldata and Eautorepair offer professional grade shop manuals at a price you can afford. Check them out!.

Hover your mouse over the REPAIR ARTICLES tab at the top of the page. The click on DIAGNOSTICS to search by SYMPTOM, TROUBLE CODE, or read TECH TIPS on how to diagnose a problem

Click on MAKE an MODEL to see all the articles I've written for your vehicle
Click on REPAIR TOPICS to read individual articles written for specific automotive systems

If you've had your car scanned and know the trouble code go to TROUBLE CODES

Here are some quick links to speed up your research

Click on the link below for speedy navigation:

ABS issues, how to bleed ABS brakes

Airbag issues or SRS light on

Alternator issues or how to test

Belt diagram or serpentine belt issues

Blower motor

Blower motor resistor

Brakes, brake issues, what kind of brake parts to buy, ABS issues

Car Alarms or Antitheft systems

Cooling system, Water pump, What type of coolant to use

Engine flush

Firing order, cylinder layout, finding #1 cylinder

MAF or MAP sensor

Oxygen sensors, How they work, How to change, How to test

PassLock or Passkey

Thermostat issues

Transmission flush

Serpentine belt diagrams

Window issues, power window motor, replace window regulator, glass adhesive

Rear Wiper Inoperative/Dead Battery—Expedition-Navigator

Rick — Tue, 20 May 2008 00:28:00 +0000

Owners of 2003-07 Ford Expeditions and Lincoln Navigators may experience a dead battery along with a balky rear wiper. The problem is covered by TSB #07-10-13 and can be diagnosed with the following procedure:

Pop the rear window open to make sure the wiper mechanism is disengaged from the motor drive plate. Next, open the beauty cover over the wiper arm attaching nut. Then, connect a dial torque wrench to the nut and rotate the wiper arm across the entire length of travel, keeping the blade touching the glass the entire time. Keep the window open during this test.

The torque measurement must not exceed 49 INCH pounds. If you discover that it is greater than this amount, replace the rear window striker/wiper pivot shaft assembly.

Corrosion on the wiper pivot shaft assembly causes excess torque and prevents the wiper arm from returning to the park position. The wiper system continues to attempt a park maneuver periodically and those continued attempts drain the battery.

The torque measurement must not exceed 49 INCH pounds. If you discover that it is greater than this amount, replace the rear window striker/wiper pivot shaft assembly.

Alldatadiy.com

eautorepair.net

Both Alldata and Eautorepair offer professional grade shop manuals at a price you can afford. Check them out!.

Hover your mouse over the REPAIR ARTICLES tab at the top of the page. The click on DIAGNOSTICS to search by SYMPTOM, TROUBLE CODE, or read TECH TIPS on how to diagnose a problem

Click on MAKE an MODEL to see all the articles I've written for your vehicle
Click on REPAIR TOPICS to read individual articles written for specific automotive systems

If you've had your car scanned and know the trouble code go to TROUBLE CODES

Here are some quick links to speed up your research

Click on the link below for speedy navigation:

ABS issues, how to bleed ABS brakes

Airbag issues or SRS light on

Alternator issues or how to test

Belt diagram or serpentine belt issues

Blower motor

Blower motor resistor

Brakes, brake issues, what kind of brake parts to buy, ABS issues

Car Alarms or Antitheft systems

Cooling system, Water pump, What type of coolant to use

Engine flush

Firing order, cylinder layout, finding #1 cylinder

MAF or MAP sensor

Oxygen sensors, How they work, How to change, How to test

PassLock or Passkey

Thermostat issues

Transmission flush

Serpentine belt diagrams

Window issues, power window motor, replace window regulator, glass adhesive

Testing an Alternator Without Blowing it Sky High

Rick — Sun, 11 Nov 2007 02:19:00 +0000

Nothing makes me crazier than reading advice that tells readers to disconnect a battery cable while a car is running to see if the alternator is any good. It’s not only bad advice, but could cost you big time in fried computers.

Here’s why: To generate power, you pass a coil of wire across a magnet. It’s basic physics #101. In an alternator, they turn things around. They rotate a magnet past a stationary coil of wire. The key here is that the magnet is an ELECTO magnetic. That’s right folks, you need a good battery to provide the power to make the electro magnet work in the first place. An alternator cannot make power if your battery is dead. This is why you cannot charge a dead battery with the car’s alternator. No 12 volts in=No 13.5 volts out. Back to the story. So when you start your car, the voltage regulator takes a look at battery voltage. If it’s at 12.7 volts, the regulator determines that the battery is in good shape and doesn’t need charging. But once you turn on headlights, a defroster grid, or a blower motor, you begin sucking power out of the battery. The regulator sees that battery drain and sends battery voltage into the “rotor” of the alternator. The rotor is the rotating electro-magnet. The “stator” is a coil of wire that’s stationary and is where the electricity is produced.

If you disconnect a battery cable while the car is running, the regulator sees total battery drain and immediately commands the alternator to run at maximum output. In effect, the alternator is now running wild. In this state, it can put out upwards of 40 volts. That’s enough voltage to fry your powertrain computer, your ABS computer, your radio, and every other computer in your car. It’s also enough to fry the guts of the alternator itself.

Are you getting the idea here? That it's not a good idea to send the alternator into ‘full tilt?”

So, how DO you test an alternator? Simple. Get a volt meter and attach it to the battery. Make sure you have at least 12.2 volts before you start the test. If the battery reads less than 12 volts, you will never be able to test the alternator. If the battery voltage checks out, start the vehicle and rev it up to about 2,000 RPM and turn on the headlights. You should see voltage go to at least 13 volts. If you vary the RPMs, you should see the voltage fluctuate between 13 and 14.5. That’s the sign of a good alternator—volts wise.

As for an amperage output test, that’s a little more difficult. You need special equipment for that. That’s where an auto parts store comes in handy. They usually test alternators for free.

Alldatadiy.com

eautorepair.net

Both Alldata and Eautorepair offer professional grade shop manuals at a price you can afford. Check them out!.

Hover your mouse over the REPAIR ARTICLES tab at the top of the page. The click on DIAGNOSTICS to search by SYMPTOM, TROUBLE CODE, or read TECH TIPS on how to diagnose a problem

Click on MAKE an MODEL to see all the articles I've written for your vehicle
Click on REPAIR TOPICS to read individual articles written for specific automotive systems

If you've had your car scanned and know the trouble code go to TROUBLE CODES

Here are some quick links to speed up your research

Click on the link below for speedy navigation:

ABS issues, how to bleed ABS brakes

Airbag issues or SRS light on

Alternator issues or how to test

Belt diagram or serpentine belt issues

Blower motor

Blower motor resistor

Brakes, brake issues, what kind of brake parts to buy, ABS issues

Car Alarms or Antitheft systems

Cooling system, Water pump, What type of coolant to use

Engine flush

Firing order, cylinder layout, finding #1 cylinder

MAF or MAP sensor

Oxygen sensors, How they work, How to change, How to test

PassLock or Passkey

Thermostat issues

Transmission flush

Serpentine belt diagrams

Window issues, power window motor, replace window regulator, glass adhesive

Starting problems – how to diagnose

Rick — Wed, 01 Aug 2007 03:56:00 +0000

I know you really want to find a serious problem and spend (waste) lots of money replacing things that aren’t broken, but the first step in diagnosing an intermittent starting problem is to clean all the ground wires. They may look OK but I’ve seen plenty of cables that looked fine but resulted in intermittent starting problems. So humor me on this and start by cleaning both battery terminals. Then clean the battery negative cable where it attaches to the engine. Then clean the battery negative where it attaches to the body. Finally, clean the cable that goes from the engine to the firewall. Still won’t start? Ok, at least you tried the inexpensive fix first.

Here's a quick diagnostic trick to help narrow down the problem: Next time it doesn't start, turn on the dome light. Then try to start it while you watch the dome light. If the light dims by quite a bit, that’s an indication that power is getting to the starter and it’s drawing enough power to dim the light. Diagnosis? Most likely a bad starter.

If the light doesn't dim, then power isn't even getting to the starter. The likely cause would be a bad or out-of-adjustment neutral safety switch. (If you own a Ford, it’s called the transmission range selector switch (TRS) and they have a high failure rate) You’ll need a digital multimeter and a wiring diagram to test out the neutral safety switch.

NOTE: Do NOT use a 12V test light unless it’s rated as “computer safe.” Many new cars run the neutral switch through the anti-theft system and those are powered by computer. A 12V incandescent test light can fry those computers.

Alldatadiy.com

eautorepair.net

Both Alldata and Eautorepair offer professional grade shop manuals at a price you can afford. Check them out!.

Hover your mouse over the REPAIR ARTICLES tab at the top of the page. The click on DIAGNOSTICS to search by SYMPTOM, TROUBLE CODE, or read TECH TIPS on how to diagnose a problem

Click on MAKE an MODEL to see all the articles I've written for your vehicle
Click on REPAIR TOPICS to read individual articles written for specific automotive systems

If you've had your car scanned and know the trouble code go to TROUBLE CODES

Here are some quick links to speed up your research

Click on the link below for speedy navigation:

ABS issues, how to bleed ABS brakes

Airbag issues or SRS light on

Alternator issues or how to test

Belt diagram or serpentine belt issues

Blower motor

Blower motor resistor

Brakes, brake issues, what kind of brake parts to buy, ABS issues

Car Alarms or Antitheft systems

Cooling system, Water pump, What type of coolant to use

Engine flush

Firing order, cylinder layout, finding #1 cylinder

MAF or MAP sensor

Oxygen sensors, How they work, How to change, How to test

PassLock or Passkey

Thermostat issues

Transmission flush

Serpentine belt diagrams

Window issues, power window motor, replace window regulator, glass adhesive

Battery Insulator – Put it back after replacing battery

Rick — Mon, 23 Jul 2007 04:07:00 +0000

If you think cold weather is hard on your battery, think again. Heat kills more far more batteries than any Arctic freeze. It doesn’t get any hotter than under the hood of an engine compartment packed with a V-6 and all the accessories. With little room for air to circulate, car makers have been forced to add battery insulating jackets around the battery to help it keep its cool. Your battery is especially vulnerable AFTER you’ve shut the engine off. That’s when all the heat rises to the top of the hood. The hood is insulated to cut down on noise. The downside to all that insulation is that it keeps the heat in and bakes your battery. If you’ve changed your battery and tossed the battery insulator, get on down to the auto parts store for a new one before your battery is toast

Alldatadiy.com

eautorepair.net

Both Alldata and Eautorepair offer professional grade shop manuals at a price you can afford. Check them out!.

Hover your mouse over the REPAIR ARTICLES tab at the top of the page. The click on DIAGNOSTICS to search by SYMPTOM, TROUBLE CODE, or read TECH TIPS on how to diagnose a problem

Click on MAKE an MODEL to see all the articles I've written for your vehicle
Click on REPAIR TOPICS to read individual articles written for specific automotive systems

If you've had your car scanned and know the trouble code go to TROUBLE CODES

Here are some quick links to speed up your research

Click on the link below for speedy navigation:

ABS issues, how to bleed ABS brakes

Airbag issues or SRS light on

Alternator issues or how to test

Belt diagram or serpentine belt issues

Blower motor

Blower motor resistor

Brakes, brake issues, what kind of brake parts to buy, ABS issues

Car Alarms or Antitheft systems

Cooling system, Water pump, What type of coolant to use

Engine flush

Firing order, cylinder layout, finding #1 cylinder

MAF or MAP sensor

Oxygen sensors, How they work, How to change, How to test

PassLock or Passkey

Thermostat issues

Transmission flush

Serpentine belt diagrams

Window issues, power window motor, replace window regulator, glass adhesive

Honda Dead Battery—Here’s the fix

Rick — Mon, 16 Jul 2007 22:59:00 +0000

Honda reports a problem with an A/C relay that can stick and drain your battery. If you drive a 2006-07 Accord Hybrid or 2003 Civic Hybrid and have a problem with your battery going dead, check the relay before condemning any other component. Find the A/C relay and remove it by pulling it out. If the printing on the relay shows that it was made by a company OTHER THAN Mitsuba, replace it. Mitsuba relays are designed to prevent the sticking problem. The part number is for the Mitsuba relay is. #39794-S04-003.

Alldatadiy.com

eautorepair.net

Both Alldata and Eautorepair offer professional grade shop manuals at a price you can afford. Check them out!.

Hover your mouse over the REPAIR ARTICLES tab at the top of the page. The click on DIAGNOSTICS to search by SYMPTOM, TROUBLE CODE, or read TECH TIPS on how to diagnose a problem

Click on MAKE an MODEL to see all the articles I've written for your vehicle
Click on REPAIR TOPICS to read individual articles written for specific automotive systems

If you've had your car scanned and know the trouble code go to TROUBLE CODES

Here are some quick links to speed up your research

Click on the link below for speedy navigation:

ABS issues, how to bleed ABS brakes

Airbag issues or SRS light on

Alternator issues or how to test

Belt diagram or serpentine belt issues

Blower motor

Blower motor resistor

Brakes, brake issues, what kind of brake parts to buy, ABS issues

Car Alarms or Antitheft systems

Cooling system, Water pump, What type of coolant to use