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Discussion Starter · #1 ·
So, one consistent problem with the '89 Conv has been that the battery will drain itself dead after sitting for a few days. I took to Youtube in search of a solution and found this video from Scotty Kilmer:
Scotty's videos are entertaining, informative, and to-the-point; I would definitely recommend subscribing to him! ;ol;

So I wired up my big resistor and meter and discovered there was about a 200 mV draw. I removed fuses until the draw went down significantly. Eventually, I pulled out fuse #24: Central Locking, 10 amps. Immediately the meter dropped to about 20 mV.

This is already over my head... How could the locking system be drawing so much from the battery? Are it's locking motors still drawing power? Could they be faulty? Anyone else had the same issue?

Thanks SaabCentral!
 

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I guess if the solenoid is still trying to close for whatever reason it'll still draw the current. I presume the c/l still works ok, are any of them sluggish in moving?
 

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Discussion Starter · #3 ·
Thanks, Steve. The central locking works great... The key unlocks all three doors, and pressing down on one lock locks all the doors, too.

Assuming there's one locking motor per door, could it just be one door that's acting up? I suppose I could open the door panels and disconnect each motor to see which one's still drawing power.
 

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Doesn't have to be any solenoid. The central locking ECU may be faulty and the quiescent current too high. This is the power it draws just sitting there waiting for a signal.
 

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Discussion Starter · #5 ·
Wow, there's an ECU just for central locking? Even on systems like mine that don't use wireless remotes? Interesting... If necessary, is replacing one of those simple and cheap? :cheesy:
 

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Not sure what year or the spec of your car. On late models it's clipped to the topside of the plastic air duct in the footwell LHS.
 

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Not sure what year or the spec of your car. On late models it's clipped to the topside of the plastic air duct in the footwell LHS.
This is one in my 1992 2.1 hatchback (it's aftermarket I think, going on the way the wiring is set up):



flickr page

Craig.
 

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Discussion Starter · #8 ·
Just to clarify, this is my '89 900 Turbo Convertible.

I managed to locate my Central Locking ECU. It's just above the air duct in the passenger side footwell. One screw to remove, then you just bend the duct down.

Bentley described testing the voltage and such. I tested pin 4 which supplies the power, and it was a strong 12 volts (using pin 3 as a ground). The manual said pins 7 and 8 are directly involved with actuating the lock motors, but I wasn't quite sure on how to test them. Once I get more time to work on it, I'll tear apart the door trim and test the wiring, I suppose. There were also other pins that went unexplained in Bentley...

In the mean time, I'll just remove Fuse 24 and manually unlock each door like the good ol' days. :roll:
 
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