Ed,

As I think someone else suggested, there are 2 primary power lines. One is permanently on, and prevents the "Gimme a code" scenario. -since it is also live with no ignition, it is used to drive the "security" light. -As can be deduced from the above, this one is almost certainly fine.

The second is the switched live. This goes live in the "accessory" and "ignition on" positions (...and usually goes low again in the "cranking" position) -If this isn't going high, the radio would think that it can't be turned on, since it thinks the key isn't in the ignition. -thus it would always give you the security light also.

-I Hope this is making sense so far.

If you like, or if you haven't yet determined the fix (sorry, -I've been away for a few days-) I have the color code from our 1995 940. I can tell you which wires are which. -assuming your car's color scheme is similar!

If you like you can check with the voltmeter. -just pick a ground for the negative test probe (-I normally hook onto some clean metal somewhere around the passenger door hinge, and sit in the passenger seat with the meter in my lap-) and using the positive test probe, look for two lives with the headlights *OFF* and the key in the "ignition ON" or "accessory" positions. If you find two, one should go off when you turn the key to "off" and remove it.

I say turn the headlights off, because otherwise there's a third wire that dims the illumination, and that'll confuse things. -It's not quite as described by a previous poster... -in fact it pulses very rapidly between zero & twelve volts. The brighter you have the dimmer control set, the more time the pulses spend high, the darker you have it set, the more time they spend negative. -This is called "pulse-width-modulation" (or PWM for short.) An analog voltmeter (one with a needle that swings across a scale) will behave a little like a lightbulb, and will show a proportional voltage, but if you have a digital voltmeter, many of these try to read the 'peak' which is always 12 volts (nominal) some others take instantaneous snapshots, and will flick randomly from zero to twelve.. hence, it's much less confusing to just turn the lights off, which removes the potential confusion.

-I like to use an oscilloscope, since this shows this clearly, (as well as looking mighty impressive!!!) but a test meter is all you need as long as you know what yu're looking for.

If this doesn't get it for you, write back... -I love a challenge!

Keith Andrews