My rear abs light light is on

Hello, I'm Danny.

Here is the information you requested. You must first check the ABS- anti lock brake system codes that are stored in your vans computer so we can determine which codes and and their number to help properly diagnose the fault. Here is a tutorial showing how to retrieve OBD1 codes:

https://www.2carpros.com/articles/ford-lincoln-mercury-obd1-1995-and-earlier-diagnostic-trouble-code-definition-and-retrieval

Once you perform this get back to us with the code number or numbers and we can then figure what the fault is. I've attached below a picture list of possible ABS codes on your van. Hope this helps and thanks for using 2CarPros.