2000 Cadillac DTS I replaced struts with ones that you can'

No, that's not true. If you install a diode, or anything else for that matter, in your ABS circuit, you will destroy your computer. Also, your struts have absolutely nothing to do with your ABS system.

Your ABS computer uses "Wheel Speed Sensors" that are small magnets mounted to the inside of the wheel hub/brake rotors. These small sensors tell the computer how fast each wheel is turning, and when you apply the brakes, how fast each wheel slows down.

When your computer detects one/more wheels slowing down faster than another, or not turning at all (wheel lock), it pulses the brakes on/off several times per second in order to regain traction to that wheel, and thus your control over the car.

Your struts have nothing to do with this. Some strut options will have ride-height controls, automatic damping adjustments, etc. But whoever charged you $980 per strut ripped you off, and in a big way!

And whoever ripped you off (and installed the struts) may have failed to reinstall the wheel speed sensors correctly. But keep in mind, these sensors sometimes fail themselves, and yours may have been ready to go anyway.

Ufortunately....the customer is not getting ripped off....I have just crossed this bridge with a customer of my own....we realized it was an electric strut, so we called the dealership. list on these bad boys is $962.88 each....needless to say....we're not installing struts on that car!