2000 E350 Brake & ABS light on OBD2 Inop

I have a 2000 E-350xlt 6.8l V10 with 330,000 miles excellent condition except recently the ABS & Brake lights are illuminated & the OBD 2 connnector will not power scanner to retreive codes (if any). I connected my scanner to the OBD 2 connector and the scanner would no power up (however the scanner does work properly on my other vehicles). I replaced the brake light switch (purchsed @ Autozone) & cleaned the rear axle speed sensor & connector with the battery disconnected. Started vehicle & Brake and ABS light reappeared after 10 seconds. Restarted van, Brake & ABS lights illuminated after approx. 30 seconds & remain on.

Normally the cheaper scanners won't pick up anti lock brake codes. Auto Zone and Advance offer free testing. I would try them otherwise you can pay for a test at some independants.
Check fuses, grounds and all electrical connections. If you have a problem with the unit http://www.modulemaster.com/ rebuilds them.
Sometimes you can clear codes and see what happens. If you recently did a brake job sometimes you can rebleed. Different pressure between front and year.

Normally the cheaper scanners won't pick up anti lock brake codes. Auto Zone and Advance offer free testing. I would try them otherwise you can pay for a test at some independants.
Check fuses, grounds and all electrical connections. If you have a problem with the unit http://www.modulemaster.com/ rebuilds them.
Sometimes you can clear codes and see what happens. If you recently did a brake job sometimes you can rebleed. Different pressure between front and year.
Thanks rhandwor, I did have a blown fuse, I replaced it and now the Datalink connector works fine and I replaced the rear ABS speed sensor and the the Brake & ABS light have dissapeared (everything is back to normal)