!999 Lumina ABS Light

Hello all - I have a 1999 Chevrolet Lumina LS 3.1 & the antilock dash light has started illuminating.
It is always off when I start the car. It lights up after I hit a steady 35
mph (or more) and stays on. This started happening immediately after I had my mechanic change the ignition wires.
My mechanic has placed the wires away from the ABS electronics, checked the connections and replaced the passenger-front speed sensor which read bad on his scanner. He's refering me now to the dealer, but I'm concerned they'll simply swap the ABS computer. My mechanic, luckily, has only charged me $50.
Any ideas from you newsgroup readers?
Thanks -
freeguy007 snipped-for-privacy@hotmail.com
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Still ABS sensors or wires. Bring to dealer or have someone that is good in electronics to check for internal resistance of ABS sensors to ABS control module. If you don't want to spend any money on right now, remove ABS fuse. If you decide to remove the fuse, your ABS light will remain lit. I had similar problem not to identify your car problem here since it involve more than sensors. However, ABS sensors failure is a common problem to most ABS system failure. Some model has traction control that also tie with ABS system so that mean if the traction control module or system has a problem, it could also trigger ABS light. All ABS sensor should have similar internal resistance. By checking internal resistance and compare the value to each wheel, I was able to track to one specific ABS wheel sensor. Front wheel sensor is more diff. to replace that back wheel.

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Thanks Paul - my mechanic said he was getting a bad ohm reading from the old sensor he replaced, but the replaced part looked good. I don't have traction control. You don't think it's ABS computer? That would be good news. Will there be a problem if I leave the fuse in? Again, thanks for your reply.

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So, if the mechanic replaced the faulty sensor with the good one, you should re-connect the fuse to test the system. If the ABS light still lit, that means the problem has not been solved.
I would try to get sensors resistance reading at each wheel and if possible with harness as far upstream as possible. I have seen ABS's harness failure at rear trailing arm where it exposed to water from the wheel well, there you will find two ABS connectors going into one harness. So make sure it is clean and well sealed. Common ABS sensor failure is at front wheel. Typical the internal resistance I have seen is around 1100 - 1300 ohms. My failed sensor read as high as 12,000 ohms at time of failure and as low as 2,000 ohms when it dried up over a month or so. Small resistance reading such as 100-200 ohms does not necessary indicates sensor failure.
Hope this help!

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