Hey guys this is the second time and I replaced the cap two weeks ago as I thought that was it. It now won't start again and I know that cap/rotor is good as it is only 2 weeks old. I think it was coincidence it started once replaced. When I opened the hood the coil was all wet from water running down on it and I had my wife crank it over and I saw some sparks go out the base. It will start once it dries out but I need it to start even when its wet out!!!
Any suggestions appreciated!

Stop that waterfall

If I could control the weather I would just get a new truck.....It gets parked up hill and rain was sideways today....

what about laying a tarp in there when a rainy day is in the forecast?

Been there, done that. I used heavy zip lock baggies to cover the coil and distributor on my neighbor's beater truck having the same issue. Kept them dry.

How old are the ignition wires? Had a 5.2L Durango that was getting harder and harder to start only when damp. Took a squirt bottle to the wires with it running. Arced all over after only two squirts and then died. Thought the wires were only a couple years old, but turned out to be a lot older than I thought!

I'd replace the coil and the wires, Once they have arced, the carbon track has already formed. Soon it won't start in dry weather. Then I would make some kind of deflector (or replace whatever is missing from the factory setup) to protect the coil from a direct water assault.

Car manufacturers usually do a pretty good job of protecting the ignition system from a direct water assault, something is missing or deteriorated to the point of not working. You need to repair or replace whatever it is that keeps blowing rain water off the coil. Gene

Where is the water coming from? I've never had an engine get wet on top in bad weather.

I thought the ignition coil on a 5.9 truck engine was on the right front below the valve cover??

As a quick fix, try spraying some WD-40 on the cap, & wires..

I did the WD 40 trick and nothing.....Yes it is on the RH side by the belt tensioner. It was soaked when I opened the hood the distributor was dry. No "factory" parts are missing this just started a few weeks ago....

Something is letting water in and that is a tough place to get wet while sitting...

I pressure washed the under hood of my 98 grand Cherokee 5.9 limited and it would not start after that.

I had to remove the plug on the coil and blow water out of it then plug it back in.

the weather proof plug goes in from the bottom on coil and makes a cup that will fill with water and short out the coil.

I put some di-electric greese in the plug holes and pluged it back in.

you may need to replace the coil or at least dry the plug out.

It started right up this mourning....I think when it gets warmer later this week I will put new wires and a coil on it. I know the coil is the original one and the wires I have no idea how old they are.....I don't know how that area was so wet sitting there unless it was pulled through the radiator as the belt was soaked also. Lots of condensate....
Thanks guys!