91 Olds Regency. For the last month or so my ABS light is coming on every now and again. It stays on until the engine is cut off, then when re-started it turns off and will stay off for several hours/days/weeks....any ideas why it'* intermittanly coming on? Is there a way to run codes to find out what'* up with this light, like the other check engine lights?

Sounds like a intermittent WSS, Wheel Spin Sensor problem. Pull the plugs and check for any damage or corrosion on the plugs.

Oldsmobile added a plastic protective sleeve to the wires going to the Wheel Speed Sensors in 1994 to correct a problem with the wires rubbing on the brake lines, wearing through and setting off the ABS light. Remove one of your front tires and look for a wire going to the wheel hub. The connection to the wheel hub is what Danthurs is telling you to inspect, clean and reassemble. When you reassemble them make sure you put some dielectric grease in the connector. Once that is done, follow the wire as far back as you can and examine it for damage such as being worn through. Fix whatever damage areas you see by splicing in new sections of wire. Make sure you solder any connections, use shrink tubing to protect the connection and cover the damaged area with a protective plastic sleeve sold at any auto supply store.

Do this to both front wheels.

If you clean the connections, and either fix the wire or confirm there is no damage, the next step is to get a scan. The diagnostic trouble codes (DTC'*) you are looking for can't be picked up by a normal scanner. You will probably need to take it to the dealer for a scan. Tell them what you are looking for so you are sure they scan the correct system on your vehicle. On a late model Bonneville there are several sensor failures that can cause the problem you are having. I am not sure which of this sensors your set up includes, but the scan will point to the source.

Most likely, if you get to this point, it will be one of your front wheel speed sensors that needs to be replaced, but the scan will narrow it down to the culprit.

Looked at wiring today and both front wheel ABS wires are in bad shape. The protective covering is all dry rotted and cracked, and the silver wiring underneath is frayed and visible. I'm assuming replacing this on both front wheels is in order. Is there anything particularly challenging about this procedure?

Depends on the extent of damage/decay to the wires. It really is just a matter of cutting out the bad sections and splicing in new wire. If you can get to all the bad sections of wire, you should be able to take care of it. If I was doing it, I would solder the connections, use shrink wrap to cover the connections, and put wire loom (plastic corrugate tube that is slit along its length so you can fit it over wires) on whatever wiring I can get to. Wire loom can be purchased from any auto supply store.