Hi all, New to forums and have some mechanical skills however I am currently stumped with a start/crank issue. I did a forums search and found some somewhat similar issues to mine, but did not see any that are exact. Problem I am having is: In hot weather turning the key produces nothing as far as starting the engine, not even a click from under the hood. This started happening when the truck had been driven, engine at operating temperature and the weather was approximately 90 degrees or more, however recently on a day that was 95 or so initial attempt to start produced the same effect. First time this happened truck sat for an hour or more and still produced same results. I was out of town with no access to tools so truck was taken to a Ford Dealership where they could not replicate problem, and produced nothing other than a bill for $185 diagnostics charge. Issue has been intermittent through warm to hot weather and up until about a month ago on a warm (operating temp) engine. The only thing that resolves the issue is to raise the hood and switch the relay in the under hood box on the driver side fender, then engine will start no problems. Not a bad relay though, because next time it happens we switch the relay with the original and car starts. One post with similar problem had a reply suggesting the ECT going to the PCM. Although in my mind if it were the ECT simply switching the relay (which takes all of 30 second if that) should not make the problem go away. Not familiar with how ECT works electronically but would also think that cold engine/hot day shouldn't be the cause. Or am I wrong on this? Truck has been out of commission last 3-4 weeks due to an ABS issue and limited time to work on cars, that son and I resolved yesterday, so I am going to drive the truck shortly and attempt to replicate fault to see if PATS may be the fault. However I am thinking if PATS were the culprit, would a simple switch of the starter relay clear it? Had considered maybe a poor or weak connection within the relay box, that removal and replacement of relay would cause temporary improvement, but truck is driven in cool/cold weather and never faults, so that isn't making much since either.