Can trunk cable harness (30623087) drain battery?

[burak25]

Hi,

I have a Volvo S40 2003 with a relatively new (3 years old) battery. As most Volvo's my trunk cable harness had problems and I removed it to solder and fix (also I had to due some work with rear license plate lights due to mandatory inspection faults).

I couldn't reach and connect the last part of this harness due to missing torx screws. Which I was guessing the alarm related parts. So I just let it as it is (connectors hanging in air) and went to a 10 days business trip. During this time my battery has been draining slowly. My car won't start but radio and other stuff keep their memory.

My question is would that be the reason for my problem? Today I had to start the car with battery cables twice and probably one more time when I am going back home. I just want to make sure it is the last connector, not something else. (Trunk lock works fine, tailgate lights work fine. And cable has been tested for shorts.)

Any opinions?

[Simmy]

try using a different battery. just because its only 3yr old dose not mean its not beginning to fail. get a load test done on your existing battery this will show any problems .alternatively get a battery optimiser to connect to your car if you leave it for long periods of time between usage

[Moose Test]

I think the key here is - did you have any kind of drain or poor battery performance *before* you modified the loom? If there wasn't, then speculation on the battery condition is irrelevant. It will be something that has happened during that work.

I had a conversation with a Volvo-owning friend only this week on such a topic. A slow parasitic drain affecting one of his newly acquired vehicles "magically disappeared" when previous additions and changes (car kits) to the audio loom were removed and repaired.

Another thought might be, how are you testing for "short"? A simple continuity tester might show no short for anything above a few ohms but not reveal a higher resistance one, which can still have a significant loading effect. Not to mention a heating effect, which you might want to know about..

[burak25]

Thanks for the replies. After testing (waiting) for a while, it became clear that the problem was the cable not being connected. After connecting the cable, using the car to charge the battery properly. Everything has been fine.
I am guessing it was causing alarm or some light to short out or something...

So for future reference: If you have problem with cable harness 30623087, always plug all the connectors...