I have a 2002 Windstar that shows ABS and Brake warning light. My mechanic checked brake fluid which was normal the brakes work fine plenty of pad and shoe material. The lights come on once in a while and go away when I restart the ignition. No particular pattern just random warning lights.

Only if the warning light showed on the dash...most often these abs sensors get clogged with brake dust or dislodged during wheel swaps if the pads are fine and fluid level correct...first check the brake pads then the disks and clean the sensors with an old toothbrush and reseat, also check the fluid level on the abs system.this should clear warning light.but any error codes stored on ecu need to be cleared using obd.

Yes it may be the wires are shorting or its actually the problem with instrument cluster.
Also get the vehicle scanned for any error codes stored in computer this will confirm whether is short circuit issue or actual problem:------
I suggest you few help links with accurate solutions to refer/go through:----Click the link below:------

Battery and brake Warning lights on Dash
http://alltypesofpartsreplacing.blogspot.com/2012/10/battery-and-brake-warning-lights-on-dash.html
--------------2002 Ford Windstar: Brake Warning Light ON dash? http://schematicsdiagram.blogspot.in/2012/06/2002-ford-windstar-brake-warning-light.html
-------------ABS & Brake warning lights remains steady on dash? http://schematicsdiagram.blogspot.com/2011/12/abs-brake-warning-lights-remains-steady.html
-----------Chevrolet Tahoe Hood open warning on dash and alarm sounds? http://schematicsdiagram.blogspot.com/2011/12/chevrolet-tahoe-hood-open-warning-on.html
-----------2005 Chevy Impala: Service Vehicle Soon Warning Light? http://whoisbyme.blogspot.in/2012/06/2005-chevy-impala-service-vehicle-soon.html -------------- Malfunction Indicator Light ON http://whoisbyme.blogspot.in/2012/06/malfunction-indicator-light-on.html
-----------Car Runs Fine But Check Engine light is ON?

http://whatisbyme.blogspot.in/2012/05/car-runs-fine-but-check-engine-light-is.html

----------
Check engine light with codes P2195 and P2197?

http://howtobyme.blogspot.in/2012/01/check-engine-light-with-codes-p2195-and.html

----------
How to Read Codes from Check Engine Light? http://schematicsdiagram.blogspot.com/2011/12/how-to-read-codes-from-check-engine.html
-------------These will help.Thanks.

It can be issue with master cylinder or the problem is there is still some air there in the system,that has to be bleed.Or else the parts replaced are not aligned properly/.I suggest everything back.

There are few help links mentioned below to troubleshoot the issue.

Click the link below and follow its procedure:-----

2002 Ford Windstar: Brake Warning Light ON dash?

http://schematicsdiagram.blogspot.in/2012/06/2002-ford-windstar-brake-warning-light.html

-----------

Battery and brake Warning lights on Dash
http://alltypesofpartsreplacing.blogspot.com/2012/10/battery-and-brake-warning-lights-on-dash.html
-----------
ABS & Brake warning lights remains steady on dash? http://schematicsdiagram.blogspot.com/2011/12/abs-brake-warning-lights-remains-steady.html
------------

Brake warning light comes on and car will not start intermittently? http://repairhelpcenter.blogspot.com/2011/12/brake-warning-light-comes-on-and-car.html
------------ When the car stops, abs pump turns ON? http://howtobyme.blogspot.com/2011/12/when-car-stopsabs-pump-turns-on.html
----------- Where is Power Brake Booster located on 1995 Lincoln Town Car? http://howtobyme.blogspot.com/2011/12/where-is-power-brake-booster-located-on.html
----------- Sometimes ABS light comes on while Driving?

http://howtobyme.blogspot.com/2011/12/sometimes-abs-light-comes-on-while.html
-----------

All types of brake problems and repairs http://howtobyme.blogspot.com/2011/11/abs-and-service-light-comes-on.html

----------
Brake Fade Issue? http://whoisbyme.blogspot.in/2012/07/brake-fade-issue.html

-----------
Brake System Troubleshooting? http://technoanswers.blogspot.com/2011/11/brake-system-troubleshooting.html

----------
Car Brake lines have no pressure? http://schematicsdiagram.blogspot.com/2011/12/car-brake-lines-have-no-pressure.html

------------
Car Brakes Dragging? http://repairhelpcenter.blogspot.com/2011/12/car-brakes-dragging.html

-------------
Car Brakes grabbing? http://repairhelpcenter.blogspot.com/2011/12/car-brakes-grabbing.html

-----------
Car Brakes Making Noise? http://repairhelpcenter.blogspot.com/2011/12/car-brakes-making-noise.html

-------------
Car Brakes Pulling? http://repairhelpcenter.blogspot.com/2011/12/car-brakes-pulling.html

----------
Pulsating Brake Pedal? http://repairhelpcenter.blogspot.com/2011/12/pulsating-brake-pedal.html

---------
Spongy brake pedal? http://repairhelpcenter.blogspot.com/2011/12/spongy-brake-pedal.html

----------
Hard Brake Pedal? http://repairhelpcenter.blogspot.com/2011/12/hard-brake-pedal.html

------------
Fading Sinking Brake pedal?

http://whoisbyme.blogspot.in/2012/06/fading-sinking-brake-pedal.html

-------------
Feels Like Brake pedal Pulsating http://repairhelpcenter.blogspot.in/2012/06/feels-like-brake-pedal-pulsating.html

-------------
What is Brake Drum Bar? http://repairhelpcenter.blogspot.in/2012/02/what-is-brake-drum-bar.html

------------
ABS light stays on but brakes work fine?

http://howtobyme.blogspot.com/2011/11/abs-light-stays-on-but-brakes-work-fine.html

-----------
Vibrations while braking On Chevrolet Van? http://technoanswers.blogspot.in/2012/04/vibrations-while-braking-on-chevrolet.html

-----------
Dragging brakes? http://howtobyme.blogspot.in/2012/03/dragging-brakes.html

------------
Brake pedal stuck? http://howtobyme.blogspot.in/2012/03/brake-pedal-stuck.html

-----------
After replacing brake rotors and pads, brake pedal remains on floor? http://technoanswers.blogspot.in/2012/02/after-replacing-brake-rotors-and-pads.html

----------
How to replace Brake Power Booster? http://repairhelpcenter.blogspot.in/2012/02/how-to-replace-brake-power-booster.html

-----------
1997 Chevy Tahoe Brake lights not working? http://technoanswers.blogspot.in/2012/02/1997-chevy-tahoe-brake-lights-not.html

------------
How to service Drum brakes? http://repairhelpcenter.blogspot.in/2012/02/how-to-service-drum-brakes.html

-----------
What type of problems usually noticed on Drum brakes? http://repairhelpcenter.blogspot.in/2012/02/what-type-of-problems-usually-noticed.html

----------
How to test Drum Brakes? http://repairhelpcenter.blogspot.in/2012/02/how-to-test-drum-brakes.html

---------
Brake Bleeder Screw Function? http://repairhelpcenter.blogspot.in/2012/02/brake-bleeder-screw-function.html

---------
Toyota Tundra: Parts diagram to replace Brake Drums?

http://technoanswers.blogspot.in/2012/06/toyota-tundra-parts-diagram-to-replace.html
---------- Squeak and grinding sound is heard when brakes are applied?

http://technoanswers.blogspot.in/2012/02/squeak-and-grinding-sound-is-heard-when.html

------------

Brake Pads Inspection on Acura Integra?

http://repairhelpcenter.blogspot.in/2011/11/brake-pads-inspection-on-acura-integra.html

-------------

How to remove Brake Pads on Acura Integra?

http://repairhelpcenter.blogspot.in/2011/11/how-to-remove-brake-pads-on-acura.html

--------------

How to remove Brake Disc Rotor on Acura Integra?

http://repairhelpcenter.blogspot.in/2011/11/how-to-remove-brake-disc-rotor-on-acura.html

------------

Brake Caliper OVERHAUL on Acura Integra?

http://repairhelpcenter.blogspot.in/2011/11/brake-caliper-overhaul-on-acura-integra.html

------------

How to remove Brake Caliper on Acura Integra?

http://repairhelpcenter.blogspot.in/2011/11/how-to-remove-brake-caliper-on-acura.html

------------

How to remove Parking Brake shoes on Acura Integra?

http://repairhelpcenter.blogspot.in/2011/11/how-to-remove-parking-brake-shoes-on.html

-----------

How to remove Parking Brake Cable on Acura Integra?

http://repairhelpcenter.blogspot.in/2011/11/how-to-remove-parking-brake-cable-on.html

-------------
Brake pedal is pulsating and vibrating? http://repairhelpcenter.blogspot.com/2012/01/brake-pedal-is-pulsating-and-vibrating.html

----------

These details will help.

check your brake fluid level, brake system, wheel sensors. Dirty wheel sensors usually cause the ABS light to come on. As for the brake warning light, it may be low on fluid (possible leak) or faulty E-brake switch.

Abs light on means the ABS sytem has a fault.
You can determine what is wrong by counting the flashes (they say) and then put the data in on the web.

IE abs, windstar, failure, 3 flashes.

The brake light on is most likely picking up on uneven brake pressure, or a failing master cylinder/
You may not feel any difference yet, give it a little time, feel for a pedal fade at a light.

it is possible but its also possible you have a wheel speed sensor acting up. you would have to have it scanned for codes

You may need to make sure that Ford Factory pads have built in sensors on them. In many vehicles these built in sensors will cause the abs and brake lights illuminate when the brake pads wear down to a certain point. Also make sure to check your brake fluid regularly. I used to work for a Infiniti dealer in the service dept. When the brake fluid was low it caused the brake lights to come on as well. Just a few things you can check out yourself before taking it in to the dealer to check for codes. 

Have you had anyone try to clean and adjust the rear brakes? You will need a shop to scan the van for ABS codes first to cure the ABS light.

Ok, check the brake fluid level for a start. This could mean a few things. Your brake pads might be worn down, which would bring a yellow warning light on(triangle), at the same time with the pads being low it will have displaced the fluid, making the level low, this would be a red light on. Now because of this the body control module has detected these faults, will have turned the abs off, hence the abs light.
If brake fluid is low, this could confirm my theory.
If its low, top up with dot 5 brake fluid and take to garage to have new pads fitted.

TL