850 central locking draining battery

Covert · Post by **Covert** » 24 Aug 2016, 22:53

I don't know matey I'll check for you

beigg · Post by **beigg** » 25 Aug 2016, 01:10

ok. keep us posted!

Post by **misha** » 25 Aug 2016, 02:09

Check for parasitic drain with digital multimeter.

Covert · Post by **Covert** » 25 Aug 2016, 04:30

Right when you take the key out it cuts the radio off and you can't turn it back on without putting the key back in

beigg · Post by **beigg** » 25 Aug 2016, 10:43

If for any reason a door switch or hatch switch is binding and does not complete the commanded lock or unlock state, the central locking system will keep trying to operate that binding mechanism.

Post by **scot850** » 25 Aug 2016, 13:48

misha has re-stated what I suggested earlier. I am like you and not the greatest on the electrical/electronic side but can get by with some guidance. So my next question is how do you know the alarm system is at fault? I may have read you said you left the car un-locked and it didn't drain the battery. Did you check the battery after a day with the car un-locked to see if the battery is draining or not, but by maybe not as much? The reason I ask is that there are a few point on these cars that can also drain the battery that are no the central locking.

So may I suggest you do the parasitic current draw test to ensure which circuit is draining the battery for sure. I thought it was the alarm system on one of my older Volvos to find it was the garage door opener that was constantly on. in a sedan the trunk light staying on when close is another as ids the glove box light staying on when closed.

Neil.

Post by **BEJinFbk** » 25 Aug 2016, 14:06

beigg wrote:If for any reason a door switch or hatch switch is binding and does not complete the commanded lock or unlock state, the central locking system will keep trying to operate that binding mechanism.

Not so.
There are no sensors that tell this relatively simple
security system if the doors are locked or not.
It just ships out lock and unlock pulses.

Post by **BEJinFbk** » 25 Aug 2016, 14:13

misha wrote:Check for parasitic drain with digital multimeter.

THIS!
After making sure that you've got the radio unlock code handy,
pull the negative battery cable and connect your ammeter in series.

Meter the current draw when the alarm is disarmed, then see what
it is when you arm the system. If it exceeds 35-50 milliamps, start
pulling fuses and see where the excess current is being consumed.

Any chance this car has the optional deadbolt locking system?

beigg · Post by **beigg** » 25 Aug 2016, 18:05

BEJinFbk wrote:
beigg wrote:If for any reason a door switch or hatch switch is binding and does not complete the commanded lock or unlock state, the central locking system will keep trying to operate that binding mechanism.
Not so.
There are no sensors that tell this relatively simple
security system if the doors are locked or not.
It just ships out lock and unlock pulses.

I've had my 850 drain the battery dead trying to engage a door lock that was not functioning correctly.

Post by **BEJinFbk** » 25 Aug 2016, 19:27

beigg wrote:
BEJinFbk wrote:
beigg wrote:If for any reason a door switch or hatch switch is binding and does not complete the commanded lock or unlock state, the central locking system will keep trying to operate that binding mechanism.
Not so.
There are no sensors that tell this relatively simple
security system if the doors are locked or not.
It just ships out lock and unlock pulses.
I've had my 850 drain the battery dead trying to engage a door lock that was not functioning correctly.

So what was the fix?