Hi.

My dad's 1996 SAAB 900 had a flat battery - it was really sudden... worked fine at 6pm, then nothing at 9pm. When he tried to start the car the dash lights went crazy.

He got a new battery next day and car seems ok BUT the ABS warning light is on - possibly an electrical fault rather than an ABS fault. Any ideas on how to fix it?

The fuses are ok, battery is ok, contacts going to ABS have been cleaned. SAAB garage hooked it up to their computer - says all ok.

is it charging is a question, is there being any charge being lost

Also is the abs actually working

only ideas i have is to try and reboot abs brain by maybe removing battery again

also did you jump start car as you might fried the brain

Its a brand new battery - the old one refused to charge. The old one also seemed ok by all tests.

ABS is working ok, so it must be elecrtrical fault - maybe the ABS relay?

Sometimes the system warning lights are controlled by the onboard computer, and can only be reset by a dealer with an OBD-II device.

For instance, one thing that I often do when I get a new car is to unplug the sensor that's used to buzz at me if I don't buckle my seat belt. It's not that I go without a seatbelt (in fact, I wear my seat belt religiously), I just put it on AFTER I've started the engine and I hate being buzzed at when the car is starting.

However on my new car, after I did that, the "SRS" (airbag) light came on and would not go out. It turns out that the SRS system uses that same sensor (or at least the wiring connector harness that I unplugged) to make a determination about whether or not to trigger a given airbag in case of an accident. Silly if you ask me, there's gonna be a driver in the driver's seat, right?

Anyway, after I plugged the sensor back in and it was all back to factory spec, the SRS light still did not turn off. It required a trip to the dealership (and an explanation, during which they gave me a dirty look) in order to get them to flip the bit in the computer that turned off the light.

It irks me that they make these products where the only solution is to report to a dealership for a (usually expensive) maintenance check. How long will it be before there are on board diagnostics which you can actually understand.