Dodge Repair: 08 Jeep Compass: no starter

Question
Hello Roland,
My brother in law has a 2008 jeep compass,yesterday I was talking to him and here's his story.
He found that after a rainy night he coulnd't get the car to start from times to times,after a few hour in the sun the car would start back and he wouldn't have problems after but yesterday the car died,here's the symptoms:
Key on,the dash lights,thieft control dash lihgt gets off,headlights on and bright(we put them on to check),parking selector in "P",then you turn on the key to start and then all the dash lights dies but the headlights stays on and bright and the engine doesn't cranck at all.
We haven't tried anything yet but he's checked the fuse and alternated a few relays.
Where would you start from  in this case ?
waiting to hear back from you.
Terry

Answer
Hi Terry,
First locate the starter motor relay in the main power box and have a helper try the start while he listens/touches that relay to determine whether it clicks or not, which is should. If not try moving the gear shift lever slightly to either side of the detent in the P and also in the N position to see if that will make it click. Also check the fuse for that relay if you know which one it is, but check all the fuses in that box as the fuse that operates the starter relay and usually also gives current to the starter solenoid switch could be blown.
The dash lights going off when you try to 'start' is not necessarily a fault as it might be normal (does he remember them staying on when the starter was cranking normally)? If this is new also then that might implicate the ignition switch being faulty. There are probably 5 sections to that switch, but the starter circuit is only one of them so it could be bad without other circuits being bad (e.g. the section that powers the dash lights).
If the starter relay does click, then the relay and current to/through it are ok, so then it has to either be the wire from the relay to the starter motor solenoid switch (which should click loudly), or the starter solenoid switch is at fault. I don't have the wiring diagrams for the Compass but will do my best.

Roland