expected current draw when car is off

I have an '87 C900 that seems to be killing batteries. After being parked for 2 weeks while I was out of town, the battery was dead (didn't even light up the dash board a little when I turned the key). I wasn't too surprised, beacuse it had been getting hard to start over the last month or so and the battery was 5 years old. So I replaced the battery. Since my truck sits outside in the cold weather, I bought a new battery for the truck and took the 2 year old battery out of the truck and put it in the Saab. Everything was fine for another month or so, and then I let the Saab sit for a week. It was very hard to start, but it finally turned over. Then the Saab sits for another week and now the battery is dead again. I realize that I put an old battery in the Saab as a replacement, but I do know the battery was good. It never gave me any problems in the truck.

Before I buy another battery for the Saab I want to make sure there is no short or something wierd going on. The first thing I want to look as is how much current the car is drawing when the key is in the off position. The only thing that I can imagine drawing power is the radio to help it remember presets, and the ECU to help it remember things that it need to remember. Everything else should be disconnected. Does anyone know how much current should be drawn from the battery when the key is off? I don't have a FSM or anything for the Saab (and I know the FSM for my Toyota doesn't give this kind of info).

I don't want to put a new battery in to have it get killed so soon, nor do I want to take it to $80/hr saab mechanics to look for a short. So I want to do as much diagnosis as I can by myself first.

Thanks! Mike

Reply to
Mike Deskevich
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I don't have an answer for you, but my '92 c900 also had a dead battery after sitting for ~2.5 weeks last month. I suppose my car is probably drawing more current than it should, but since I very rarely leave it sitting for more than a day or two (after which it starts perfectly) I decided not to worry about it. I have an aftermarket radio and XM receiver, and both of these things draw current to feed their memories, so that may be at least part of it.

These questions could be easily cleared up with a multimeter and a little spare time.

John

Reply to
John B

First thing to check is the glove box light, followed by the under-hood and trunk lights, make sure they're all turning off.

Reply to
James Sweet

Well......

Batteries sometimes do just die like that.

For a tiny fraction of $80 you can buy a basic multimeter ( on Ebay for example ) that will measure the current for you.

Graham

Reply to
Pooh Bear

In my 87 900 it was the seat belt retractors that were drawing current when the car was parked.

John

Reply to
Captain Freedom

Oh I forgot to mention those, ripped them out at the very first opportunity and replaced them with standard belts. Wonderful car overall but those power seatbelts are downright idiotic, probably far more people who would have worn their seatbelt simply unclipped the automatic ones than those who wouldn't have worn it but did because it was automatic. It's right up there in the top 10 worst automotive inventions of all time.

Reply to
James Sweet

yeah, i already have a multimeter, and when i recharge the battery i plan on measuring the current. i just wanted to know what to expect. obviously, i know i shouldn't see 1A or so, but i don't know if 100mA or 10mA is reasonable or not.

Reply to
Mike Deskevich

ah, never thought of that. and now that i think of it, they've been acting up lately. thanks for the hint!

Reply to
Mike Deskevich

is there a kit to replace them? or how did you do it. i've always hated them.

Reply to
Mike Deskevich

Interestingly, my old 99/C900 hybrid current draw was largely attributed to either excessive radon exposure from the Canadian Shield - or - electromagnetic disturbance caused by the Northern Lights.

Ahh, for the salad days when the SAAB dealership was held by Jaguar Canada..

In early 90's it was all finally shorted when Big Mike Keane and I re-loomed the engine bay from the dash forward using delco gear whilst an exceptionally interesting native MicMac healing prayer involving sweetgrass and trout(s) went on in the lock-up next door.

.. :) ..

Depending on your year, there was a factory problem with some high-voltage bundled looms that saw excessive bay heat and age related resistance deplasticize the wire jackets over time.

Eliminate the obvious first of course.

But, just to make sure you are in on this - that trunk 'light' has introduced more stylish couples on a starry October nights to the 'eastern delights' of the C900 cargo bay than anything else engineered into the package. I always kept a good thick Canada National Pullman blanket in the back of ours in case just such an opportunity arose.. Squire..

Anyway, then start poking around the bundled wire where it meets the engine or a grommet in the shell. If you see any colour bleeding in the jackets or anything is kinda chalky - carefully dig a little deeper and look for green stains anywhere.

Depending - then have any competent euro-centric shop go over anything you can't eliminate or is as above.

Reply to
Dexter J

Try a google search, there is (was?) a page detailing how to do this, if you can't find it I can try to explain it but it's easier when you have all the pics. Anyway the deal is you find an '86 or earlier 900 with good belts at a junkyard and pull them, then most of the job is pretty much a straightforward swap, other than some modification or replacement of a couple trim pieces. If your headliner is sagging then get the headliner out of the same car you get the belts from and redo that one, if you can use the trim from that car as well you'll have a really slick complete job.

Reply to
James Sweet

Thank the US government for those, they weren't Saab's idea. In '87 or '88 a law was passed that all _imported_ cars had to have either passive belts, or airbags. Airbags weren't ready (to Saab's standards) by that time, so that's why we have the mousebelts.

As you say, they probably cause more problems than they solve. As happens so often, a bunch of lawyers came up with a law with unintended consequences...go figure.

Reply to
Dave Hinz

Then you've solved it. They don't go all the way to the back, so the limit switch never says "shut off", so they keep drawing current. The fuses are, I think, under the back seat behind the driver seat. My '88 did that, I ended up getting them into the right position, pulling the fuses, and having an extra clip to fasten every time I got in the car.

Dave Hinz

Reply to
Dave Hinz

either excessive radon exposure from the Canadian Shield - or - electromagnetic disturbance caused by the Northern Lights.

Hey Dexter, I don't know what you just changed in your newsreader, but your line length is now at 200+ characters.

Reply to
Dave Hinz

Have you checked to make sure the boot/trunk light is not on? C900's don't have the light in the boot/trunk set up with any switch that's activated by the movement of the boot/trunk lid or hatch so if you leave that light on by mistake it'll stay on and with a normal lamp installed it'll pull about 0.9 A continually.

Also if you can remove the cover over the ingition switch assembly and measure the voltage on the terminal corresponding to the 'S' wire. That is supposed to only be connected with there is a key in the ignition lock barrel, but it might be staying live all the time and whatever draws power from that wire might be putting a parasitic load on the battery when the car is not running.

Regards,

Craig.

Reply to
Craig's Saab C900 Site

Fortunately those wierd devices have never been put into cars here - I think they're horrible and IMHO quite dangerous.

Craig.

Reply to
Craig's Saab C900 Site

One more thing, see if you can confirm that the alternator is working. If the charging light on the dash comes on when you start the engine and stays on all the time, that means that the battery charging circuit (in the voltage regulator on the back of the alternator) might have failed. Replacment voltage regulators can be bought for about US$15 from a couple of Ebay sellers.

Craig.

Reply to
Craig's Saab C900 Site

Must have been later than '87, my '87 Volvo has neither power seatbelts (thankfully Volvo never used that garbage) nor airbags, something else I'm not entirely sold on, but at least airbags are not invasive so long as nothing goes wrong with the system.

Reply to
James Sweet

While I was still looking for suitable replacement belts I did spend some time screwing around with the silly automatic ones and got them working ok for a while. What I did was take the whole assembly apart, wash the old lube off the cable and then grease it up with new stuff. I also at one point had to fix the wire to one of the end position microswitches, but the lube is the main problem, it dries up and the whole mechanism gets sluggish and jams up. Probably not worth the time to muck with though, I like Dave's idea better, disable them while you look for a suitable junker to get the parts from.

Reply to
James Sweet

A friend of mine did require stitches in the end of his finger after it got caught in the track of one in a Ford Escort, perhaps he should have sued the government for requiring the stupid things but it'd probably just be a waste of time.

Reply to
James Sweet

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