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Re: Car is a 94 Aero... Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Mon, 24 Nov 2008 20:25:09
In Reply to: Car is a 94 Aero..., Steve C., Mon, 24 Nov 2008 15:17:23 Members do not see ads below this line. - Help Keep This Site Online - Signup |
If a 10 amp fuse is blowing, something is pulling a lot of current. I would fear for the transistors in the ECU that drive the BPC. The BPC has two coils, joined at the center point that ties to fuse 5. Transistors (2) in the ECU connect to ground. So if one of the BPC coils fails shorted (as they can do), it will cause the transistor in the ECU to see a lot of current, which can fail it.
Or, you're 'lucky' and have a short to ground. When you're measuring the continuity between the BPC and the ECU, have you tried measuring to ground to see if there is a short? Disconnect the connectors from the ECU and the BPC, and measure pins 1 and 3 to ground (resistance). They should be open circuit; if not, you've got a short to ground.
There are usually A LOT of connections between 'things' in the electrical system - there has to be. If there were direct connections between each sensor, switch, and light bulb and the circuit driving it, the electrical harness would be a huge octopus that would be impossible to install. It may look that way, but thankfully it isn't. The electrical harness is actually a series of harnesses that interconnect through various connectors.
As to the schematics - the diakom schematics are just copyright-violated prints from the Mitchell schematics, which are pretty generic. The Mitchell schematics are a general tool for shops, and leave out lots of information.
I have some of the Saab electrical manuals. Saab doesn't have a single shop manual; for any model year, there are a series of manuals - electrical, engine, suspension, etc. As an example, the 1997 electrical manual runs to just shy of 400 pages. Each electrical system (door locks, AC compressor, interior lights) has its own section, running to 5 or more pages. A detailed schematic with wire color and size, all connectors, etc. A theory of operation section and troubleshooting info. Even drawings of each of the parts and where they are located in the car, including all connectors and ground points.
If you can find the electrical book for your year car - sometime available on FleaBay - buy one. The difference between it and the Cliff Notes Diakom schematics is astounding. But if all you've got it diakom, it's better than nothing.
posted by 76.252.197...
, Mon, 24 Nov 2008 13:58:04, Mon, 24 Nov 2008 20:25:09 <-- Viewing This Message, Tue, 25 Nov 2008 22:51:50
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