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Discussion Starter #1
Ever since my beloved 93 900 convertible got into a head-on collision with another vehicle on a slick road I have had terrible issues with battery drainage after it was repaired. If I let the car even just sit for an evening the battery is completely drained.

I’ve checked all the fuses, I’ve spent thousands at this point taking it to various auto shops, and have been though no less than 5 batteries in a year. I’m at my wits end, I love this car so much and this is the only issue that is wrong with it.

I would be eternally grateful suggestions
 

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There is a hood switch that detects an open hood and turns on the trunk light to trigger the alarm system. That may have been mishandled in a body repair. A black wire to the left of the hood latch as I recall...
Be very sure the trunk light is not on.
 

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Discussion Starter #4
I opened the hood while the car was off and all trunk lights appeared to be off both on the trunk hatch and the interior (also made sure the trunk interior light toggle switch was set to off).

Is there a way of checking if it's the Alternator diode, that's under the hood, correct (is it the attached image?)
273136
?
 

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You can use it in ammeter mode across fuse terminals to see where a draw is. It's a pretty fast way to track down these types of problems. Just be sure to use a safe range when testing so as not to damage the multimeter... most will have a "high" setting and a "low" setting, like a 10a and a 1a (1000ma....) setting. Start with a high, multiamp setting (which may require moving the red probe) and place the probes across both sides of where a fuse was. Now, the multimeter is the fuse and you can see if something across the other side is drawing power. If it is, see what the fuse controls and then move the test downstream... or, unplug what's at the other end and see if it stops. You can even do this for the alternator - remove the battery cable, and place the multimeter between the cable and the terminal on the alternator.
 

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Discussion Starter #8
I went through this video:
- basically hooking the meter up between battery and terminal and one by one pulled each fuse and relay.... for some reason it seems there's a continuous 12.8v draw and unless somehow I missed something blatant that draw did not decrease with the fulling of any fuses or relay. I'm a huge novice here when it comes to this stuff - I really appreciate the help!

273241
 

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Well, that kind of makes sense. So you may be looking for something that isn't fused. Did you try removing the B+ terminal from the alternator, or disconnecting terminals from the battery junction by the cabin air intake?
 

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Discussion Starter #11
I removed/reinserted all the fuses and terminals by the air intake too. It fairly quickly drops to the decimal when I remove the B+ terminal from the battery. Removing the B+/red line from the alternator itself still doesn't decrease the read on the meter - very confused as to what could possibly be sucking up that much power
 

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AND the timer. You start the timer every time you hook up the battery. There are several circuits involved in the timer. You have an alarm, unplug that too.
Then do thetest again. You should get down to about 0.058 amps.
 

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Your alarm module is under there too.
That black hood switch wire I mentioned at first can make the alarm keep trying to arm itself. A body shop, seeing a black wire, may have grounded it.
No matter what, get rid of the things that are autonomous: alarm, timer, any aftermarket accessory (radio, alarm, amplifier, disco lights...Whatever).
 

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With the car not running and key out (reverse lock key out position if manual or P if auto), have you tried putting a clamp type meter over the battery positive cables directly at the batt+ terminal to measure the 'baseline' current draw? Once you know what that is, start phyically isolating every circuit you can either by pulling fuses, or even disconnecting the various batt+ feeds from the distribution block in the engine bay, and observe what happens.

If by doing that you do not get close to zero (whatever the standby current would be for clock, audio head unit, maybe alarm) and still have some fairly significant (say 0.5 amp or higher) static current draw, then you need to start checking things connected to the 'terminal 30' (direct from battery unfused) circuit. The starter motor is the primary item on that, but are other things. Starter will draw zero current when 'off', and the solenoid is not on the terminal 30 circuit so it can't be that.

If by pulling fuses and/or disconnected feeds to parts of the elec system at the distribution block you do identify significant drops in current draw, then you have narrowed it down somewhat. If there was a broken wire or terminal directly shorting that's something that needs to be found asap.

Make sure there aren't any lights still on when everything is switched off - a single small light bulb can drain down a battery over time enough to make cranking problematic.

Are there any fused additions beyond the factory wiring that don't have fuses in the normal places? Normally an alarm won't have an obvious fuse (because then it's pointless!).

Re under the rear seat yes depending on year and config there are fuses under the rear seat.

Layout of the under-seat fuse/relay panel and the table of what relays and fuses are present for configs and build years that have it:

https://flic.kr/p/2j1NvPx
https://flic.kr/p/2j1SJDw
 

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Discussion Starter #17
So I started disconnecting batt+ feeds from the distribution block (after switching the multimeter over to the + terminal) close to the passenger side air vent. When disconnecting the lefthand feeds the power drain immediately decreases from around 13v to 9v (it looks like the thickest cable is the culprit - does that feed into another terminal or?). So there is a 4v continuous draw just there. (I also disconnected ALL the cables going from the battery to that terminal - same 9v draw). I re-attached those on the left terminal to - back up to 13v & again removed the wires attached to the alternator (both the small one and the other one under the SAAB cap) - there was no change in power consumption.

Could there be multiple drains or maybe a major split wire leaking electric (is this possible?). I am completly dumbfounded as to where such a massive draw could be going.

Screen Shot 2020-05-14 at 4.49.32 PM.png
 

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Soooooo.... electricity doesn't work that way. :)

If you think of electricity as plumbing, voltage is a measure of water pressure and it flows from where this some to where there isn't any - from a battery to a light bulb or a starter for example. If there's a blockage - in plumbing a buildup in a pipe or in a wire corrosion or a loose connection - less pressure (voltage) may result. That's voltage drop - the difference between the source and what makes it to the destination.

Amperage is the volume of water flowing through the pipe, or the amount of electricity flowing through the wires. Amperage is a function of what's on the other side of the source. A light bulb consumes relatively few amps, but a starter consumes a whole hell of a lot of amps. The limit here is what connects the source to the destination - too small a pipe or wire means the volume will overpower the conduit and fail.

To use the water analogy, if voltage is a river the grade of that river represents the number of volts. A flat river is low pressure and low voltage. A waterfall is high pressure and high voltage. Amperage is the size of the river. A trickle of water from a light rain is low amperage. The Nile is high amperage.

Voltage is an indicator of consumption - where there is no consumption there will be no voltage. So you can use voltage to track the "idea" of consumption (including voltage drop, or blockages), but not the nature of it. To measure consumption, you need to look flow, or amp draw.

Measuring amp draw means routing electricity through a measuring device. For this activity, that measuring device is a multimeter. That's done in the ammeter section, not the voltmeter section. You can do it on the positive side or the negative side, but it's MUCH easier (although less safe...) to do it on the positive side.... we have readily exposed fuses on the positive side, but all our grounds are tied together in a few specific locations.

The process is: Multimeter in ammeter mode, remove a fuse, and place the one probe of the multimeter in each of the terminals where the fuse was. Now you're measuring how many amps were flowing through that fuse, how many amps the thing is drawing from the battery.

From your photos and descriptions, you have the multimeter in DC voltmeter mode, which can help for gross issues but I think you've run into the wall on that. You really need ammeter mode, and you really should be testing at the fuses for accurate, usable results.

From your photo, it looks like you've got a Klein CL110, which only has a transformer-based clamp for measuring amp draw, and unfortunately that is not useful for measuring DC amps... it's the wrong type o' clamp, and more to the point for this exercise you really don't want a clamp-type ammeter anyway since you're measuring terminals. :(
 

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I have not read all the posts.
So apologies if I am out of order.

I had a similar issue with my 92 900s vert.

Killed 2 batteries.

In my case it turned out to be a faulty relay under the rear seat.
 

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I should have been more specific in saying that the OP needs to be measuring DC current flows via the battery positive connection and disconnect things via removal of fuses or disconnection of sub-circuits. My bad there as I forgot that a regular clamp meter is designed to use on AC circuits not DC circuits. Apologies for that bum steer.

A reliable scientific way to measure a DC current is with a high-current shunt of a known resistance so measuring the voltage across the shunt itself gives the current flow via Ohm's Law. High-current shunts are often used in off-grid solar power systems to measure in-circuit current.

The battery terminal voltage doesn't give the full picture as when the engine is running the terminal voltage will be 13.5 to 14.5 volts (due to the alternator), and when it's off the battery should sit at 12.0 to 12.5 volts but in a subcircuit with a handful of links the measured voltage at a relay or switch could be between 11.0 volts or less (when engine isn't running). Batteries will 'self discharge' over time if not regularly used/charged.

The primary source of DC electricity in a standard motor vehicle as we know them today is always the battery and never the alternator.
 
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