Mechanics

POWER FAILURE

2007 Buick Rendezvous

Electrical problem
2007 Buick Rendezvous 6 cyl Front Wheel Drive Automatic 45000 miles

periodiclly the vehicle wont start. It appears the battery does not have enough power. It will start with a jump. The dealer tested for a voltage draw but could not find one. The battery and alternator have been replaced (less than 2 years ago). Dealer noticed some corrsion on the battery cable and cleaned that up, but problem happened 2 weeks later.
something is causing the vehicle to loose power when it sits overnight. It only happens periodically, and more often when it is a cold night.
dealer appears to be incompetent. I need your help.
Thank you for your consideration.
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Jr1darby
April 17, 2010.




Hi jr1darby,

Thank you for the donation.

Such problems are rather tricky and is not going to be easy to diagnose.

Quite often it is a sticking relay that causes intermittent drains on the battery.

Have you ever noticed any electrical components that does not shut off when the engnine is not running?
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KHLow2008
Apr 17, 2010.
Everything appears to turn off when car is not running.
This problem seems to happen in the cooler months and not in the summer.

Tiny
Jr1darby
Apr 18, 2010.
When problem occurs, is the battery completely drained or just weak?

Parasitic drains would normally get the battery flat and if it is only weakening the battery during colder weather, it could be the battery is the cause.

When did this problem start occuring?
Is your battery the maintenance free type?

KHLow2008
Apr 19, 2010.
The battery is not completely dead; the interior lights all work. This has been happening for about 2 years. It is a maintenance free battery from the gm dealer. It is the 3rd battery. The car was at the dealer 2 weeks ago and they stated that the battery and alternator are fine.

Tiny
Jr1darby
Apr 19, 2010.
Maintenance free batteries are known to fail intermittently. They could be good one moment and the next you won't ba able to start the vehicle though all components works. It can work everything except the starter.

When the battery is good, testing would not showanything. I have encountered a few such cases.

Since the problem had been present since the battery was replaced, maybe you can try a swap of batteries with another vehicle to test if the problem goes away.

KHLow2008
Apr 19, 2010.

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