reversed polarity
 

My father-in-law left my wife some ranch land and a 2000 dodge 3/4 ton dually diesel (no modifications). We have used it for just ranch chores the last 5 years. Recently it started getting hard to start. Charged the batteries and with a boost it would start but the next day not enough juice. I pulled the batteries and took them to the local "irish" auto parts store. They sold me 2 new batteries which I installed. When i hooked up the first battery sparks flew when i touched the positive cable to the battery post. I looked at the post and saw that what I thought was the postive post was negative. The posts were reversed from the batteries I had removed. Drove back to store and as I walked in the man who had sold me the batteries says "I gave you the wrong batteries, didn't I". Yes you did I replied. He exchanged for the correct batteries and assured me that no harm would have been done. Now the truck will not start. Turns over fine....just never fires up. The "wait to start" light does not come on. There was a 140amp fuse (circled in yellow) burned out and one of the relays (circled in red) would hum loudly. I replaced both and tried again ...same result. I am not terribly mechanically inclined so I am looking for ideas on what else may have gotten. "fried" as a result of the battery post reversal. Thanks for your help.

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