Sons 2007 Jeep Liberty Won't Start

[Daveh]

Hey Guys,

My sons 2007 Jeep Liberty V6 won't start.  It does nothing.  The lights in the dash turn on like when you start it but nothing else.  The fuel pump is turning on and the car is not setting off any codes.  I tested the battery and it was in great shape (only a year old) and I even took it to Napa for them to test and it was the same results as mine.  The starter is fine. I get no clicking or anything when I turn the key.

Any thoughts?  Thanks

Dave

[Brads70]

I hope yours fares better than my son's . His did that  but was doing crazy stuff with the dash trouble lights, and it turned out to be the main computer was fried. We ended up scrapping it as it was too expensive to fix.

[Daveh]

Thanks for the tidbit of info.   

It's been running fine so I'm hoping it's something simple that someone here can help me with. 

[Chryco Psycho]

Computer switches the ground for the relay , might be the problem

[Daveh]

Can you explain a little further please? 

Could it possibly be the ignition relay???  Thanks

[Chryco Psycho]

yes could be a bad relay in the power box

[Daveh]

I just switched the starter relay with the wiper relay (they were the same) and nothing still the same result.

What's next?

[Chryco Psycho]

What if you short the 2 heavy wires at the relay

[Daveh]

Do you mean like this? 

https://www.youtube.com/watch?v=aV-uAdftl7o

How do I know which ones to jump? 

[Chryco Psycho]

exactly , either the 2 largest terminals on the relay or if 3 terminals are in line & 1 faces across it will will be the odd one & the one opposite to it

[Daveh]

Ok the good news is that after Chryco's suggestion of shorting the terminals where the relay was the car started right up. 

Now what is that telling me?  What do I need to replace?  Thanks

[Chryco Psycho]

Probably means the computer is not closing the circuit to ground the relay to allow the engine to crank over , check to see if the alt is charging , take a reading before starting & a reading running , it must be higher when running usually 13-8 -14.2 v at the battery running , 13.2 not running

[Daveh]

But if the alt wasn't charging wouldn't  the battery be drained?  The battery is fully charged. 

[Chryco Psycho]

Brad was saying when his computer quit starting the vehicle the computer would also not power the alt , so no charge

[Daveh]

Ok I'll test it thanks