I have a 2000 yukonxl 2500 that the abs and brake lights both come on when you hit a bump. More predonimant in warm weahter. I have taken it to my local garage and mechanic says he has many GM vehicles with this problem. He says there is not an error code to indicate the abs needs to be replaced. He has a number of technical bulletins from GM telling him to clean and lubricate the electrical connections. The device is temporarily loosing power.
He has done all he can and it has not solved the problem.
I have the same EXACT problem. I thought I was nuts. It is worse when it is warm outside and happens when you hit a bump, go over a railroad track etc. My mechanic has also done all he can and the problem persists.
One of the sensors probably isn't grounded properly or it has broken internal parts. That is why it flickers when you hit a bump. The weather issue should not come into play, so i find that weird.
A technician can sit inside the car and watch the lights while someone else lightly taps each sensor until you find the bad one. First clean it and the surrounding area. Also wiggle the connection where the sensor plugs in. If neither of these procedures work, replace the sensor.
