Will not start?

ROJOMO

MEMBER
2007 JEEP GRAND CHEROKEE
3.7L
6 CYL
4WD
AUTOMATIC
190,000 MILES

Seems to be something with either the ignition switch or the lock cylinder. The car sometime won't start, everything comes on, (lights, radio, fan, etc.) But the engine won't start. It is entirely random. It will start sometimes by waiting (the first time it happened I had it towed, when I got it home I t fired right up). Sometime moving the key back and forth works. I would just like to fix it, but I want to make sure if it's either the ignition switch ($50) or the lock cylinder ($150).

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,667 POSTS

Hi,

Before we replace things, we really should check a few things.

When it doesn't start, do you hear anything from under the hood? For example, do you hear the starter click?

As far as which part to replace, that's a tough call without taking things apart. However, please keep in mind, the problem could be the starter or even a dirty or loose battery cable. Check to make sure they are clean and tight first.

If they are good, see if it starts in neutral. If that is unsuccessful, have a helper turn the key for you while you place your fingers on the starter relay to see if it is clicking. The relay is in the power distribution box under the hood. See pic 1 below

If there is a clicking, then go to the starter motor. There will be a yellow wire with a gray tracer. Have the helper turn the key to the start position while you check for voltage to the yellow/gray wire. It should only get 12v with the key in the start position. If there is power, the starter is failing. If there is no power, then we need to check at the switch.

Let me know what you find.

Joe

See pic below.

Image (Click to make bigger)