Rendezvous TSB

[rendezvous]

Would anyone be able to help me with this TSB? Buick has tons of TSB regarding the Rendezvous and now I have a Rendezvous experiencing this electrical problem. The car will be fine for days or even weeks, then one morning you come out to start it and the battery is completely flat. Like someone left something big on all night. This problem doesn't have anything to do with how long it sits, although it has to be overnight or several hours. Temperature doesn't matter, it can be 50 degrees or 8 degrees, it may happen, it may not. Nothing obvious is staying on interior lights, glove box, map lights, all go out after allotted time after exit.

This last time I didn't touch anything and started digging. There was a 2.5 amp draw somewhere?? By the time I got into it, probably from opening doors, etc., it went away.

That's what brought me to the internet, and here. This TSB sounds exactly like what this car is doing and it does have an XM radio and rear seat audio, both of which are part of this TSB.

Besides the inconvience of coming out in the morning to a car that won't start, I'd rather not end up replacing the battery too! How many times can you kill a battery this bad and expect it to recover?

Any suggestions based on experience or the TSB, would be greatly appreciated !!

TSB No.: 3024 NHTSA No.: 10009639

Thanks

Steve

[shadams]

Neither of those numbers mean anything to me..

What year Rendevous? Let me know and I will see if I can find it and see what we can come up with.

As far as the battery, it can go dead and be recharged several times, but it is definitely going to shorten the life of it over time, no way to know how much though.

BTW, there are tons of bulletins on everything, all a bulletin is is info on a certain problem that someone found and fixed with the help of GM tech assistance and they in turn put out the info so we dont have to call them when we service a car. It doesnt by any means mean a car is a heap or anything like that, just makes our jobs a little easier.

[rendezvous]

Shadams.....THANKS!

The Rendezvous is a 2004, it has an XM radio and rear audio.....if those matter. The TSB I was reading the summary on says those do matter. The odd thing about this problem is it is so infrequent. The car has been sitting several days unused and today I went to start it...no problem, started right up battery is still fully charged!

The only connection we have possibly made is it may have something to do with the heated seats???? Maybe??

I'll greatly appreciate any input you can give! Thanks again in advance.

I know many TSB's don't mean the car is a heap. Maybe it is a reflection on how many were sold and what issues have come to light. There sure are alot of Rendezvous on the road where I live. They've been a real good seller.

[firebird1324]

hmm...sounds like you have a pretty good sized parasitic drain. you said it happens at different time intervals too, so that means you've got an intermittent problem. one of the only ways you really have to check it by yourself is either a.) sit and wait after you shut the car off for however long it takes your modules to fall asleep and see if anything noticable stays on, or, turn your car off, get yourself a voltmeter, put it on amps, put it in series with your battery positive cable, let it sit for about half an hour, and see if you've got anything drawing amps. if you do, it's time to start pulling fuses and doing the same amp check, if you have a draw larger than a few tenths of an amp in any given circuit, you've found your problem. on the rendevous, you should have a fuse box under the hood, under the drivers side dash (i think) and one attatched to your bcm (body control module) and that is located in the center stack of your passenger side.

or, take it to a GM dealer, and they can do the same check in alot less time. (there is a special tool that elminates the half hour waiting time, and the need to disconnect your battery.)

[shadams]

Here is the specific info for that bulletin:

On vehicles built prior to 5/1/04, a condition may exist if a vehicle is equipped with RPO: U2K (XM Satellite Radio), UQ3/UK6 (Rear Seat Audio), and any radio except UC6 (6-Disc CD Changer) and UM8 (Navigation Radio). This condition exists only after the ignition has been turned off after RSA has been left 'on' and the RSA XM satellite radio source has been selected. If left in this state the vehicle could experience excessive battery draw. From all appearances, the radio and RSA are off, but this is not the case. This draw could range from 2.0-3.0 amps and result in a dead battery.

If significant battery draw is present when RSA is 'on' and RSA XM band source is selected prior to turning vehicle off, observe the Tech 2 message monitor for active modules including radio and DRR (Digital Remote Receiver). If the DRR and radio are active on the Tech 2, there may be a software issue with the radio causing this draw. If either or both of these two modules stays active, contact a radio exchange center and request part number 10376762 (CD) or 10376760 (Dual). Note: The exchange centers will only provide the listed part numbers and accept '03 radios for exchange for vehicles with the concern and RPOs mentioned above.

So the first step is finding out when it was built. Either open your dr door and look at the tag on it or the door jamb, it should have a build date, or PM me the vin and I can pull it up. If it was built after the date above it will already have the updated radio in it and this wont apply. If it was built before, then your only option to see if this is what it is, is to go to the dealer, as they need to use the scan tool to see if this is what is happening. If no one uses the rear radio controls, then it probably wont be it, as it states you would have to have turned it on with those control in order for it to stayt on after you shut off the car.

Before we go any further, lets see if this might apply, let me know....

Oh, and Firebird1324 gave some good advice, the only thing I would add is you would actually put it in series with the negative cable, not the positive. The max draw is 30 milliamps, or .030 amps. Anything more than that and you will have drama.

Here is so really good info from GM, it describes what we would do to determine if a vehicle has a drain, and how to try and track it down:

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:

Build the vehicle.
Select the Engine section.
Select the Engine Electrical sub-section.
Select Diagnostic Information and Procedures.
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.

[firebird1324]

^good call shadam, i was just racking my mind trying to remember how we tested for parasitic drain. listen to him on the drain specs, not my few tenths...and the negative cable is a better choice =)

[rendezvous]

Damn..........You guys are good! I'll try to answer all your questions completely and accurately.

1) I'm one step ahead of you on the ammeter. With it in series with the battery, on initial shut down and exiting the vehicle, the drain is 6+ amps. After approx. 2 minutes(interior lights shut off) the drain falls to 2 1/4 amps. After another few minutes(less than 10) the drain falls to an amount indetectable on 10 amp scale. This is when everything is working right. Vehicle will start as normal after several hours or several days. I have duplicated this condition several times.....no problem.

2) Vehicle build date: 10/'03

3) 2 young kids ride in the back regularly........the rear radio probably gets turned on and off ....or just on regularly.

4) Although the RSA is used regularly, the XM band wouldn't be selected, only the FM or CD player modes.

5) One time the drain of 2+ amps stayed on, the battery was already just about dead (interior lights were very dim). By the time I threw my charger on it, got the cover off the fuse panel to start pulling fuses, it went away.

6) Your post:

On vehicles built prior to 5/1/04, a condition may exist if a vehicle is equipped with RPO: U2K (XM Satellite Radio), UQ3/UK6 (Rear Seat Audio), and any radio except UC6 (6-Disc CD Changer) and UM8 (Navigation Radio). This condition exists only after the ignition has been turned off after RSA has been left 'on' and the RSA XM satellite radio source has been selected. If left in this state the vehicle could experience excessive battery draw. From all appearances, the radio and RSA are off, but this is not the case. This draw could range from 2.0-3.0 amps and result in a dead battery.

definitely gives me some ideas! As I said before, does have XM radio, does have rear seat audio, does not have 6 disc changer, and does not have a navigation radio. This seems like a condition I should be able to duplicate.

And you're right right Firebird, it is a pretty big parasitic drain......when it exists. The car has been sitting for 4 days, it is 7 degrees out this morning, and it started right up.

Your thoughts and input are greatly appreciated Firebird and Shadams! I'll get back with you after I try to duplicate this condition again!

Steve

[rendezvous]

2/28....I cannot duplicate the problem. Still trying though!

Following your advise re: current draw and parasitic drain, and trying many different combinations with the radio when shutting off the vehicle, nothing acts up!

Haven't given up though.....will be on it today!

Steve