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john -aka eauto
john -aka eauto, The Car Guy
Category: Cadillac
Satisfied Customers: 12953
Experience:  15 years as a auto tech
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I have a 1998 Seville STS. The battery keeps running down.

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I have a 1998 Seville STS. The battery keeps running down. I have taken it to the Caddy dealer 3 times. They could not find any shorts. the residual draw was 8 mille amps which they say is correct. I have had the ride computer, generator and battery replaced (twice) but they have not corrected the problem. The new battery after 4 days of driving short distances shows 12.4 volts. With the engine running I get 14 volts. No battery warning light comes or info messages come on. Other than the message "14.1 volts battery OK. I would think the message should say 12.4 which my digital multimeter show. Eventually, the battery drops to below 9 volts and the car wont start and the security light is dead when the door is opened. Can the ride system be the cause or a defective charge relay(diode)? The same thing happend after a long drive. Any ideas? thanks Ken Ball, Rye New York XXX@XXXXXX.XXX(NNN) NNN-NNNN
Submitted: 4 years ago.
Category: Cadillac
Expert:  john -aka eauto replied 4 years ago.
most likely has a parasitic draw

 

A car battery is used to store electrical power in reserve to be used when the car engine is started. Several conditions can occur that will cause a battery to lose its charge overnight. There are several "live" electrical circuits that can draw electrical power from the battery when the key is in the off position

  • As a battery ages it loses its ability to hold a charge, as a rule of thumb a battery will last about three to four years. If the battery is fairly new you will need to start the engine by jump starting or charging the battery using a battery charger. Once the engine is running test the alternator in the charging system. If the alternator fails, replace it with a new or rebuilt unit and re-test system, if the alternator tests ok proceed to the next step.
  • This first test is simple but you would be surprised at how many people simply leave their headlights on overnight. If the battery is dead check the headlight control switch. If the switch is in the on position turn the switch off and jump start or charge the battery. The battery should re-gain its state of charge after about 15 minutes of driving and your problem will solved. If headlight switch is off proceed to next step.
    mechanism fails it can leave the interior light on draining the battery. If this is the case the interior light delay sentinel or Body Control Module will need to be replaced. If all tests ok proceed to next step.

  • Inspect the car stereo tape deck or CD player, sometimes a tape or CD will get stuck in the player either loading or ejecting causing the motor inside the tape deck to stop. This small motor can draw enough electrical power to drain the battery overnight. If a tape or CD is stuck in the player try using a small flat bladed screwdriver or small tweezers to remove the culprit. If the stuck tape or CD will not come out. Remove the player and disconnect the unit. Once the unit has been removed either replace the player or send it to a stereo repair shop and reinstall when repaired. If player tests ok proceed to next step.

  • Inspect the glove box illumination light, in most cases this light is controlled by a small pin switch. If this switch malfunctions or is misaligned it will allow the glove box light to stay on draining the battery down overnight. To check for this condition look for the light inside the glove box through the small cracks in the glove box door. If this light is illuminated when the glove box door is shut replace or readjust the switch to operate properly and recheck light operation. If it tests ok proceed to next step.
  • Inspect the car stereo tape deck or CD player, sometimes a tape or CD will get stuck in the player either loading or ejecting causing the motor inside the tape deck to stop. This small motor can draw enough electrical power to drain the battery overnight. If a tape or CD is stuck in the player try using a small flat bladed screwdriver or small tweezers to remove the culprit. If the stuck tape or CD will not come out. Remove the player and disconnect the unit. Once the unit has been removed either replace the player or send it to a stereo repair shop and reinstall when repaired. If player tests ok proceed to next step.

  • Inspect the glove box illumination light, in most cases this light is controlled by a small pin switch. If this switch malfunctions or is misaligned it will allow the glove box light to stay on draining the battery down overnight. To check for this condition look for the light inside the glove box through the small cracks in the glove box door. If this light is illuminated when the glove box door is shut replace or readjust the switch to operate properly and recheck light operation. If it tests ok proceed to next step.
  • Inspect the trunk illumination light, in most cases this light is controlled by a small pin or a mercury level switch. To test the trunk light operation observe the light as you close the trunk lid, the light should go off when the trunk lid is nearly shut. If the light doesn't go off replace or readjust the switch and recheck operation. If it tests ok proceed to next step.
  • Inspect the hood (covers the engine) illumination light, in most cases this light is controlled by a small pin or a mercury level switch. To test the hood light operation observe the light as you close the hood, the light should go off when the hood is nearly shut. If the light doesn't go off replace or readjust the switch and recheck operation. If it tests ok proceed to next step.
    debris that can cause an electrical draw like a penny or a gum wrapper. Anything that can cause an electrical draw will drain the battery power. If debris is found remove it with a small pair of tweezers. (Note: sometimes when inserting tweezers or removing debris from the cigarette lighter a fuse can blow, if so replace the fuse with new after the debris has been removed) If the lighter is ok proceed to next step.

  • Inspect the electric seat control switch, this switch can become sticky or weak allowing the switch to stay engaged forcing the seat motor to draw power from the battery until dead. To check for this condition observe the operation of the seat control switch if it does not return the neutral position or is sticking in one position replace the switch with new and recheck.
  • If no other electrical accessory is causing the battery to drain overnight a manual draw check of the electrical system will need to be performed. What this means is you will be checking the electrical draw the battery has on it when the car is locked up, with the key in the "off" position". First open the hood and disable the under hood illumination light, if equipped. Next, with the key off and the doors locked wait 15 minutes, then disconnect the battery cable on the negative side. (The 15 minute wait allows the computers to go into "sleep mode" and shuts down all electrical). Attach a test light between the negative battery cable end and the negative battery terminal. The test light should illuminate dimly or not at all. If the test light is on brightly there is a strong electrical draw in the system. To locate this electrical draw start removing fuses one at a time. When the test light goes out the circuit in question has been located. You will need a car repair manual to identify all accessories in a particular circuit, repair as needed and re-check system.

  • Customer: replied 4 years ago.

    The info you provided I already knew. I believe I have an intermittant problem which at this moment is not evident. I will once again try pulling all the fuses time to pull all the fuses. A 12 volt bulb connected between the battery negative and the battery negative lead when disconnected lights makes the bulb filament glow but not fully lighting up the bulb. I cannot get a milleamp reading that makes sense so am waiting for a friend to try with his meter. Is 8 milleamps the correct residual current draw. I belive that is what the Caddy dealer service mgr told me. I am also going to try again pulling all the fuses. I have been told that there is a bulletin out about the STS electrical problem (s). Do you have them?

    Expert:  john -aka eauto replied 4 years ago.

    Bulletin No.: 02-06-03-010A

    Date: July 02, 2004

    INFORMATION

    Subject:
    Battery Parasitic Drain

     

    Models:
    2005 and Prior Passenger Cars and Trucks
    2003-2005 Isuzu Light Duty Trucks

     

    Supercede:

    This bulletin is being revised to add the 2004 and 2005 model years. Please discard Corporate Bulletin Number 02-06-03-010 (Section 06 - Engine).

    In automotive terms, a parasitic drain is an electrical load that draws current from the battery when the ignition is turned off. Some devices, such as the PCM and the radio memory are intended to draw a very small amount continuously. These draws are measured in milliamps (mA).

    In normal use, parasitic drains aren't usually cause for concern, because the battery is replenished each time the vehicle is driven. But, in long-term parking situations, parasitic drains may discharge the battery enough to cause a no-start condition. New vehicles in dealer stock and airport long-term parking are two such situations.

    An abnormal parasitic drain could be a glovebox or luggage compartment light that remains on but undetected. Or an electronic component may malfunction and cause a parasitic drain that is larger than normal specification.

    Parasitic Drains and On-the-Lot Battery Discharge

    Important: In most cases of discharged batteries in low-age, low-mileage vehicles, proper charging procedures with approved charging equipment is the only repair necessary.

     

    Here are some rules of thumb that might help relate parasitic drains to how long a battery would last on a parked vehicle. The Reserve Capacity (RC) rating multiplied by 0.6 gives the approximate available ampere-hours (AH) from full charge to complete rundown. Somewhere between full charge and complete rundown, the battery will reach a point at which it can no longer start the engine, although it may still operate some of the electrical accessories.

    Using up about 40% of the total available AH will usually take a fully-charged battery to a no-start condition at moderate temperatures of 25°C (77°F). Put another way, for a typical battery in a storage situation, depleting the available AH by 20 to 30 AH will result in a no-start condition.

    Important: If the battery begins storage at 90% of full charge, reduce the available AH accordingly.

     

    The recommendation for maximum parasitic drain is around 30 mA (0.030 amp). A typical drain today actually falls into the 7-12 mA range, even though some vehicles do approach the maximum. Multiply the drain (in amps) by the time (in hours) the battery sits without being recharged. The result is the amount of AH consumed by the parasitic drain. The actual drain may be small, but over time the battery grows steadily weaker.

    Here's an example: a vehicle with a 30 mA drain and a fully-charged 70 RC battery will last 23 days. But if that battery is at only 65% of full charge (green dot barely visible), it is going to last only 15 days before causing a no-start.

    Effects of Temperature on a Standing Battery

    The parasitic drain will be fairly constant over a range of temperatures. The important temperature is that of the vehicle at the time a start is attempted. Colder temperature raises the threshold of a no-start by increasing the residual power needed. When the temperature falls to 0°C (32°F), the battery will be able to put out only about 85% of its normally available starting power, and the engine may need as much as 165% of the usual power to start.

    The combined effect of these two factors is to reduce the number of days the battery can stand with a parasitic drain. At 0°C (32°F), the battery can stand only half as long as it could at 25°C (77°F). And at -19°C (0°F), the standing days are reduced to one-fourth.

    Temperatures above the moderate climate of 25°C (77°F) increase the battery's internal self discharge. If the battery is in a locale where the temperature is averaging 32°C (90°F), an additional 5% to 10% of the available ampere-hours will be lost in a month due to self-discharge within the battery. At temperatures below the moderate range, self-discharge will be low enough to be negligible compared to the parasitic loss.

    What the Policies and Procedures Manual Says About Parasitic Drains

    Because determining how long a battery may last in a storage situation is not precise, the P & P manual provides a clear-cut policy, excerpted here.

    "Discharged batteries can freeze at temperatures as high as 0°C (32°F), causing permanent damage. Other permanent damage may result from allowing batteries to stand discharged for extended periods."

    "To alleviate this condition, the negative battery cable should be disconnected on vehicles which are not going to be in service within a 20 day period, beginning from the time the vehicle is shipped. If this is not possible, batteries should be recharged periodically, every 20-45 days, until the green eye is visible."

    "Disconnected batteries will slowly discharge, especially with higher temperatures; therefore, even disconnected batteries should be checked every four months and recharged if necessary."

    "Vehicles on display are subject to battery discharge due to drains from courtesy lights and other accessories. Provision to maintain battery state of charge for these vehicles will be necessary."

    Consult your P & P manual for full details.

    Tracking Down the Source of a Parasitic Load

    If the battery in a vehicle becomes discharged in a shorter time than described earlier, the vehicle may have an out-of-specification parasitic load. Refer to Service Information (SI) for procedures for locating parasitic drains. Follow these steps:

    1.Build the vehicle.

     

    2.Select the Engine section.

     

    3.Select the Engine Electrical sub-section.

     

    4.Select Diagnostic Information and Procedures.

     

    5.Select Battery Electrical Drain/Parasitic Load Test.

     

    You will need the J 38758 Parasitic Draw Test Switch and a digital multimeter set to the 10A scale.

    Important: Read the procedure and follow the steps exactly as described in SI. The following is a summary, not the complete procedure.

     

    The test switch permits you to place an ammeter in series with the battery negative cable. Before performing the test, the engine must be run and all accessories must be operated as instructed. After shutting the ignition off, turn the test switch off. Now, all the current being used by the vehicle is shunted through the ammeter where it is measured. If the reading is out of specification, the procedure explains how to pinpoint the cause.

    A Final Word About Battery Testing

    Your dealership has an essential tool, the Midtronics Micro 410 Battery Tester, J 42000. Use it to quickly identify batteries that are serviceable and can be charged. Refer to Corporate Bulletin Number 02-06-03-006A for more information about this tool.

    john -aka eauto, The Car Guy
    Category: Cadillac
    Satisfied Customers: 12953
    Experience: 15 years as a auto tech
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