08 XK Limited will not start.

[mrnavy2]

Ok, here is my problem. Last weekend did a tune up on a 08 XK Limited. It ran beautiful after replacing the upper plugs. After a few days of driving it and enjoy how she ran, I parked it at home and the next day went out to start it and it would not start.
What I get when I turn on the key: I get a small click. My friend listened to where the click was coming from. It was coming from the back fuse back. We opened up the fuse box and start to check everything. When we heard the click again, it was coming from the group of 3 relays. Everything lights up on the dash. Windows go up and down, Radio and AC still work.
I also checked the battery and it was 12.5 volts. Still good, but it will not start. We also try to jump start it to satisfied ourselves and still nothing.
Anyone had this problem or heard of this kind of problem on a 08 XK.. Thanks for your help. Steve….

[07JeepXK]

Did you try jumping it off of another vehicle with jumper cables?

[NeilSmith]

battery. trust me, battery. jump it and see if it will start. lots of talk over the past few years about the batteries. you cant trust the battery testers neither. also could be wire running to starter, if it starts by jumping it then ts the battery.

[07JeepXK]

Its not the battery! He posted on the other forum. They tried to jump it off his friends truck. Still wont start. Doesnt even turn over at all but all the lights qork, windows go up and down...etc. Im thinking starter..

[NeilSmith]

then starter or that stupid wire down there. Its not the battery ! HaHaHaHa !!

[Matt]

Steve, put a voltmeter across the battery and see what the voltage drops to when you try starting it. If the voltage drops, its likely the starter. If the voltage doesnt drop, its the wiring and/or relays.

Want me to take a look at it tomorrow AM?

[Matt]

Just an FYI, since you told me it didn't start a few weeks ago but then randomly started working again.... I have a feeling its corrosion on the wiring harness.

[mrnavy2]

Ok all, here goes… My friend Matt came over this morning and some of you may know him.. A very knowable guy also with a XK. He did a few checks on the battery and relays. Seems like everything there was ok.. Then he said, lets jack up the XK and he got under the XK and shook the Starter Wire Harness and BINGO the XK started… Mat is a Life Saver. I have been so down since Thursday trying to figure out what was wrong. Mat came over and in 10, well maybe 15 minutes had it running again.. Then we drove the XK to the jeep dealer, to have them install a New Starter Wiring Harness tomorrow. THANKS TO MAT, I was back on the road. And also Thanks for all you guys and girls for your feedback. Steve….

[Matt]

We'll have it figured out in a few hours.
12.5 is normal for voltage when not running. The key is what the voltage drops to when he tries starting it. A good battery will stay above 10 volts while cranking. If it drops below that its not enough to turn the engine over.

[07JeepXK]

Starter!!