Something is draining my car battery.

[Mb0345008]

Something is draining my car battery. I was having trouble starting my car and it eventually wouldn’t start at all and my interior lights wouldn’t come on automatically like when I turn the car off and open the door. Sometimes when I was on the highway and accelerating the battery light would come on for a couple seconds and then go away. That didn’t happen too often though. So we replaced it with a brand new one and it started up strong and the interior lights came on.
My check engine light came on and the code was a bad temperature sensor. Now I can tell that my battery is slowly draining because the interior lights aren’t coming on again and I got that battery error light when I was on the highway. It lasted about a month before it started to deplete and it’s not very fast but I know that within a month or two it will be dead again to where I won’t be able to start it and I would like to get to the root cause of this.

There was also a little weird thing happening where when the air would come on it would only come through the defrost vents and then a loud click noise would happen and it would start coming out of the face vents (The ones it was supposed to be coming out of) This only happened a few times and was not a super common thing. I wanted to add that in there just in case it fits in anywhere in this situation.

 

[2007LucerneCXL]

Have you checked the alternator yet? You stated you replaced something, which I assume was the battery, but you didn't say what was replaced. Most parts store can check the alternator to see if it's putting out the correct power or there's information on the net on how you can check it with a meter. Eliminating the common stuff can help in getting to the area where this may be the problem.

 

[Salvaing]

Your battery is discharging and to find the leak, you have to put an ammeter in the circuit. (Engine stopped and key removed).
You must read :
- door open : 6,00A (PCM / BCM active + several lamps are lit)
- door open after 30 seconds : 1,87A (PCM / BCM active + some lamps go out)
- closed door : 1,53A (PCM / BCM active + some lamps go out)
- door closed after 1 minute : 0,15A (PCM / BCM active + Alarm ON)
- door closed after 2 minutes : 0.02A (Alarm ON)
In fact PCM + BCM go into standby gradually, which leads to the leakage current of 0.15A to 0.02A
With a consumption of 0.02A, only 0.5Ah disappear every day ... it takes 2 months to stop the vehicle to empty half of the battery : reasonable.

If the ammeter displays 0.025A to 0.05A or more, it means that something is consuming battery.
Remove the fuses one by one until the ammeter goes to 0.02 and you find the circuit responsible of the leak.
In 95% of cases this method gives good results.
The only cases where it does not work :
- short circuit elements not protected by fuses, for example alternator or glow plugs ... good but in this case the leak is greater than 3 A
- vicious leak, random so very difficult to find ...

 

[richardnewton]

1. Parasitic drain testing to get you started

2. This month, we did some battery-alternator maintenance on the Vous. This improved charging performance and reduced resistance within system.

First, check wires and connections for damage. Check alternator belt tension. Have auto parts store test battery and test alternator.

A few highlights of what we did:

- Cleaned battery terminals
- Replaced positive corroded OEM terminal bolt
- Replaced negative corroded junk bolt/multi-washer terminal bolt some mechanic hacked on
- Replaced corroded thick original washers interfacing with both battery terminals

- Cleaned main ground bolt/wire ends/body connection (above passenger side headlight)
- Cleaned terminals on alternator

This video and comments got us started

 

[Tomislav]

Something is draining my car battery. I was having trouble starting my car and it eventually wouldn’t start at all and my interior lights wouldn’t come on automatically like when I turn the car off and open the door. Sometimes when I was on the highway and accelerating the battery light would come on for a couple seconds and then go away. That didn’t happen too often though. So we replaced it with a brand new one and it started up strong and the interior lights came on.
My check engine light came on and the code was a bad temperature sensor. Now I can tell that my battery is slowly draining because the interior lights aren’t coming on again and I got that battery error light when I was on the highway. It lasted about a month before it started to deplete and it’s not very fast but I know that within a month or two it will be dead again to where I won’t be able to start it and I would like to get to the root cause of this.

There was also a little weird thing happening where when the air would come on it would only come through the defrost vents and then a loud click noise would happen and it would start coming out of the face vents (The ones it was supposed to be coming out of) This only happened a few times and was not a super common thing. I wanted to add that in there just in case it fits in anywhere in this situation.

I have exactly the same problem...
Did you found what was the problem?

 

[Francesca]

I just bought a 2002 Rendevous Jan 25. The gas tank was leaking so the dealer replaced the tank and the blower on the air conditioning which was included in the sale. The sales man said he also had to replace the battery but when I asked why he said because he was a nice guy. He didn't know really. Anyway we drove it home and the next morning the battery was totally dead. No lights. No ignition even the door lock wouldn't work. We recharged the battery and brought it back. We picked it up the next day and brought it home. The next day the battery was dead again. This happened a time and I was getting very upset. He kept it 3 days to be sure it was going to start. When I went to get it he said some sensor that talks to the brain had gone bad and they replaced it. I haven't had any problems with the battery since then. I don't know if this helps but ya never know! Good luck