[wsmm]

I have a 1990 wt1500 work truck with a five spped manual. This Friday my brake light in the dash gave me a trouble code of 8. This time it only turned out to be a dirty connection, but as a result when I looked it up in the manual it said it could also be the dump valve. Just what is the purpose of the dump and iisolation valve? If they went bad would it still be save to drive the truck? The dealer as usual was of no help what so ever, just wnated me to bring the truck in and let him work on it. Fat Chance!!!!!