Thanks. I know the ABS does not directly run off vacuum. But as you say, the master cylinder boost does. So if I have a vacuum leak, that is probably why the ABS light came on as well.

So to find an air leak on a diesel I have heard you can spray ether on fuel fittings with the engine running and if idle increases then you have found it. Could I do something like that on my gas pickup? Has anyone ever tried that?