I have a 1990 Bronco and the ABS Light keeps coming on. I have a Haynes manuel and it shows me the connector for checking RABS codes but it doesnt work. I drove my truck til the abs light comes on 90 seconds hahaha; left the engine running so i dont lose the codes and tried to ground the wire under the dash but no codes flashing.

Am I doing something wrong????
Also under hood on the left fender wall next to the EEC Connector there is a connector labeled RABS TEST.

What is that one for?

Thanks for the help