What would cause the abs brake motor to run when pressing lightly on braks

the ABS is a system that allows wheels that have stopped turning under brakes to turn again momentarily
the brakes work through the abs system normally at all times from the booster and it is only when a wheel stops turning that the electric motor in the abs unit provides pressure to a line to compensate for the fluid returned by the valve in that line that was opened when the wheel stopped
you can disconnect power to the abs ( fuse ,relay) and the brakes will still operate normally except that when in extreme braking situations the wheels will lock up and steering control will be the same as pre abs cars ( side skid and not able to steer around an object)
there may be a abs light come on but you will have to live with that
best talk with an accredited brak specialist shop as they may have an idea as to what can be done to bypass the abs
remember that the abs is part of the vehicle safety requirements and in by passing it or making it inoperable you may be making the vehicle un-roadworthy for the purposes of inspection and insurance.

ABS is automatic braking system. Check brake fluid, if full Thats not the problem. Take to Dealer or trusted brake shop. Brakes are an very important safety device. It's not a DIY thing to do.

You proberly have a bad wheel sensor that is causing the problem. When this light is one, you don't have the ABS braking feature in operation. You should have brakes, just not ABS. ABS braks are a saftey feature that helps prevent wheel skids on slippery roads.

This indicates you have an issue with your ABS control unit. ABS is a system that "pumps" the brakes in rapid succession to prevent wheel lockup during an emergency start. A common cause of sliding in wet weather, etc. To do this a computer control module uses plungers to open and close the brake fluid flow to the brake in miliseconds..so while you are pressing on brake pedal hard... the system is actually applying and releasing the brake in rapid succession (miliseconds) to prevent skid, etc. When teh computer module goes bad the ABS and Parking brake light will stay illuminated. There shoudl be an ABS fuse in your vehicle (please refer to your manual) that can be removed. Remove this fuse and check it for dirt, blown, cracks, or corosion. Replace the fuse and listen with the motor off if you hear a hum noise this would indicate the motor is running continuously for the brakes and is another indicator of a bad control. With the fuse removed both lights should stay continuously lit. If the motor is running continuously this can blow the ABS motor.. your brake system will still function with the fuse removed, but test it with a slow roll (no gas hand pushed car) The ABS controller is quite pricey to replace in the vehicle and should be referred to a licensed facility such as a dealer. YES dealers are high but to have this job done properly you need to have the vehicle raised on a platform. Your local brake shop, muffler shop, shadetree wont be able to do this control repair properly.

when mine did that, it meant the brak abs system was not funtioning....check fluid level

i'm not entirely sure on this but it sounds like the assist is not working, i think it works with the power steering , so check htat level, and the belts, i hope this helps

how do i fix or reset this fault
Engine system fault,park brake faultengine system fault, park brake fault & dsc not avilable

IF YOUR ABS LIGHT IS ON YOU HAVE ABS PROBLEMS LET THE DEALERSHIP FIX IT.SOUND LIKE MASTER CYLINDER PROBLEMS.ITS CONNECT TO ABS MODULATOR.YOU NEED A TECH 2 SCANNER TO RELEASE THE TENSION MOTOR IN MODULATOR.YOU CANT FIX IT AT HOME.ITS A DEALERSHIP JOB..

Locate and pull the ABS pump fuse located in the power distribution center under the hood and CHECK IT TO SEE IF THE FUSE IS BAD. Basically you are looking for a fuse box with large amperage fuses and some relays. Look along the fender well in the engine compartment relatively close to the battery. It is a 60 amp fuse in most instances and should be clearly labeled "ABS" in the large fuse box with other similarly oversize fuses used for other high power subsystems. 
 All ABS systems are designed so that the solenoid valves in the ABS brake manifold are in safety "bypass" mode when powered down or when the ABS control module has been removed. You will have standard everyday power brakes no different than brakes built without the ABS system.

The ABS system will perform a self check once you exceed 5 MPH and the "ABS" and "brake" lamps should turn off. During this test, the controller runs the pump motor and briefly operates all of the valves. This ABS "self-test" is performed every time you start and drive.

EBCM is short for "Electronic Brake Control Module" It is the advanced computer than controls the electric motor pump and valves of your ABS system.  Burnout of the motor is very rare however. A MOSFET transistor in the EBCM (Electronic Brake Control Module) has failed, can cause the pump not to perform.

Pump motors generally do not fail, but when they do, the culprit is usually worn-out brushes or corroded electrical connections. In a worst-case scenario, your motor is beyond repair. It is bolted directly to the hydraulic assembly- a cast aluminum brake fluid distribution hub with 5 or 6 brake lines branching off of it and wiring harness.

I hope this helps before you get your hands to dirty. In short check all the electrical connections first. Try running a hot wire to the pump motor first to see if it runs and if it does, then it's not the motor and could be a easier fix by changing the (EBCM).

There is a known failure of the ABS system control board which typically causes this problem. THere are companies out there that will rebuild your current board (if it's rebuildable). Do a search on ABS repair in Moscow, Iowa.

They will rebuild the module for $150.00 and warrant the repair for 5 years (as opposed to up to a $1000 form GM, and no guarantee as to how ling it will last.).

I did this to my '01 Tahoe and am real happy with it. The company offers diagnosis tests to help you determine if the problem is your ABS module.

Reply back what you find.