When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I would try to get the trouble code if you have access to a scan tool. You can also check some of the basics first, brake pads, fluid level, any leaks, and fuses.
Good luck with the early Bosch scan tool...that was an "off-board" diagnostic tool and was d/c by GM right about that time. Later models had ABS incorportaed into the system, so there was only one scanner for everything instead of a special scanner for abs only,.
Often a intermittent abs lite means you have a wheel bearing going south,. as the bearing gets loose the tolerance for the sensor changes and triggers the lite. Grease and dirt on the sensors also cause it.
Get ABS parts for that yr and earlier from FleaBay. Some of the big ticket items like modules can be bought from the catalog stores. Sensors..lines, used only. Older Mercedes use the same system and so did Caddys. Someone said that Porche did too.