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Discussion Starter · #1 ·
Not wishing to seem incredibly common and predictable, but I have an inexplicable flat battery on my 9000. It hadn't given trouble for ages until today when the battery was depresingly flat and wouldn't turn the engine. Had to jump start it.

The battery was new 6 months ago and I know it kept going flat before it was replaced. The only thing I noticed was that the driver's heated seat had been left switched on (first time i'd used it), could this somehow have allowed current to flow over night?

Normally the voltage reading is about 13.6 when running. I noticed that the reading is about 7-10 when first started, but if I press info a few times it's on 13-14 when it comes back round.

Why oh why? Silly car.
 

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Hello, I reckon that the seat is wired through the Seatbelts On light thingy, so it would of sensed you not there (?!?) and ignored the selection. Thats how the passenger seat on my Aero worked the other night when I was out in it and suffering from boredom so I had a little play.

As far as the dash readings are concerned, my local Saab dealer said "ignore them, they can be a little bit odd at start up". Maybe the problem is in the alternator overcharging the battery and therefore boiling the water/acid off.

HTH
 

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Discussion Starter · #3 ·
Really? How intelligent. How saab. But I don't think there is a sensor under the drivers seat. It just assumes there's a driver.

Either way I'd hope that the seat wouldn't heat with the ignition off. But you never know.
 

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Originally posted by Peteysmithy:
[qb]Really? How intelligent. How saab. But I don't think there is a sensor under the drivers seat. It just assumes there's a driver.

Either way I'd hope that the seat wouldn't heat with the ignition off. But you never know. [/qb][/b]
I just tried it!! If I sit on the drivers seat with the car running the seatbelt light is on, if I am out of the car the light is on. If I get in a clip in the seatbelt the light goes out. But, the pasenger seat is different, if I press down on it the seatbelt light comes on!, but the drivers one is on whether I am in the car or not!! I'm none the wiser, it probably doesn't help in the slightest, hopefully a grown up will be along soon to clear this lot up..

 

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I thought there was no sensor under the driver's seat. As far as seat belt warning goes it assumes that, if the ignition is on, that there is a driver.

I never checked this on my old 9-5SE, but on my 02 Aero I tried to heat up the cold leather seat by running the engine while I scraped off the ice. But the seat was still cold. It warmed up promptly once I sat in it though - so there must be a sensor for the heater, at least in 02 cars.
 

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The seatbelts light is worked from microswitches in the seat belt anchor point being operated by the insertion of the buckle, putting the light out. However the front passenger seat has also a simple contact below it that is brought together by the weight of a person sitting on the base, (if you ever see it you'll understand why I havn't given it a grandiose name like a 'pressure switch'). This has to be together to bring on the Seat Belts light.
Not sure if it also has control over the passenger heated seat pad, but it's possible.

The drivers seat does not have any sort of sensor, well not on the seats I've had out anyway.

Nick.
 

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Ahh, that's what I was supposed to be writing about!


Well Peter, you could check the terminals of the battery, try taking them off (remember to have security codes at the ready etc) cleaning them with emery paper (where they make contact) then reconnecting them. Check the other ends at the starter motor and negative earthing point while you're at it as well.

HTH.

Nick.
 

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Discussion Starter · #10 ·
Hmmm. Can't rule out the boot light this time.. but it usually goes out fine. I disconnected the bonnet light already because I thought it looked shifty but that hasn't helped.

I'll check all those contacts. I think the alt is new, but I'm worried that people have said about 14v is normal. I've never ever seen 14+v on my 9000. But then I'm going by the dash reading. Is there a contact on the alternator I could check?

Tried shouting at it earlier. Didn't work much.
 

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Discussion Starter · #11 ·
Oh, I have seen the wimpy little switch thing that lives under the passenger seat. It fell off and I broke it between two fingers trying to re-attach it.
Had to put it all back together. Fiddly soopid little thing.

But having fixed it my car seemed a bit less demented.

PS. This isn't an excuse to start on seats again guys!
 

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you aren't the only one with the low readings at start up mine is down at about 9-10 volts at start up but ease's its way up to 13.6volts its never been above this i was wondering if it was a fault but the car seems fine to start and run! Hope you find a cure for yours
 

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a voltage less than 9 on start usually means the battery is on the way out (or the contacts are coroded /loose )
I would start by cleaning every thing if you use an abrasive make sure all particles are removed as these are usually a good insulator
nip up all contacts nice and tight and slaap some vasaline over them
crank it(when cold ) and see if its still <9 if so change the battery

good luck
 

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Peteysmithy,
if you have a multimeter, connect it across the battery terminals. With the ignition off a good battery should show in excess of 12V, maybe about 12.5 -12.7 volts. When the engine is running it should rise to at least 13.6 volts and more normally about 14.2 volts. Raising the revs from tickover will probably show a slight increase in volts. You should then turn on as many electrical circuits as possible (headlights, heated rear window, heater fan on full speed, etc) and see that the battery voltage is maintained. The voltage may drop as each load is switched in but should come back up quite quickly. If the voltage isn't achieved the alternator isn't puting out enough power and the battery is being under charged. The alternator should be more than capable of producing enough power to supply the heated seat and all the other electrical needs of the car.
Ignore the low voltage readings on the EDU. Mine, even with a new battery sometimes reads as low as 7V. The EDU records the lowest voltage during cranking but that would appear to include spikes of very short duration.
With the multimeter in current mode you could, with the ignition OFF, connect it in series with the earth strap. This should show up any leakage current to earth which may be draining the battery. It won't help you find it though but alarms are notorious for this. DON'T turn the ignition ON with the meter connected like this or you will blow the meter.
If none of this proves anything maybe you just have a duff battery!
Finally there are no sensors in the drivers seat for the heater pad it is simply switched on with the dash switch and needs the ignition on.
 

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I've never yet tested a car and found zero current when the ignition is off.

Even my Morris 1000 Traveller (pause... nostalgic sigh... deep breath.. continue.. ) drew a few milliamps. Reason? The stereo I'd fitted drawing a bit of current to keep it's station memory alive.

On the Saab at the very least there's a flashing LED to supply!

I'm never sure what is a reasonable current draw... for example, 50mA on a 90Ah battery would take 75 days to run it flat, so something of that order would be OK I guess.
 

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I suffered with a low battery voltage and slow cranking for ages with my 9000. I tried to find the source of the drain (as did my dealer) but we never came to any conclusion, other than maybe it was the alarm, but each time this was tested the drain was minimal.
After a new battery (slightly bigger capacity) which was then replaced under battery warranty twice
, some time later the starter began to stick and wouldn't run when it was very hot.
My local garage removed the starter motor and found it very sticky and full of carbon brush dust, after cleaning, lubrication and reassembly, it turned over faster than it had ever done, even with a new battery. I never had any further problem
 

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Heated seats should not drain battery as only operate when ignition is on. If a new battery, I wouldn't have thought they would drain a battery overnight. Sounds like a poor connection to me somewhere - could it be an earth strap or even the connection to the starter motor?

Mike
 
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