2005 Random no start

[dagan06]

I have been working on my mother-in-laws car. She has a 2005 sedan with a random no start. When the car doesn't start the battery is dead and a jump will get it started. I have replaced the battery and the alternator with no luck. Any suggestions where to start?

[dagan06]

Also car has 94,000 miles

[shorod]

Have you confirmed the battery is actually dead when the car won't start, or are you just assuming that's the case because a jump start will get it going? Does the starter do a single click when the key is turned to "Start" or is it a rapid series of clicks? Have you confirmed that the cable connections are clean and tight at the battery? How old is the battery?

-Rod

[dagan06]

the battery is not dead. I still have power windows and they move fast. I replaced the terminals when I replaced the battery in May.

[dagan06]

Also had the starter replaced.

[shorod]

Okay, in the original post you stated, "When the car doesn't start the battery is dead and a jump will get it started." I'd still like to understand what does and does not happen when the car won't start.

Is there any noise, such as the click of a relay, or the loud click of the starter solenoid?

Is it a single click or a rapid series of clicks?

Have you had her try to start the car in Neutral instead of Park?

Do the lights in the instrument cluster come on with the key in Run and go out when turned to Start?

-Rod

[dagan06]

It does nothing no clicks at all. The dash lights up like it should but the battery light comes on and it doesn't normally come on

[shorod]

Are you positive the battery light doesn't normally come on? Usually the battery light will come on when the engine is not running, at least as a bulb check.

If you have a multimeter you should consider having someone attempt to start the engine while monitoring the voltage at the battery. If monitoring on the battery directly, see if the voltage drops significantly. If not, try the same thing measuring on the cable ends at the battery. If now you see a significant voltage drop (but not on the battery posts directly) you have a connection issue. If you don't get much voltage drop when the key is turned to Start then either the starter is not getting a signal to engage or the starter solenoid is faulty. If that's the case, the first thing to try is to depress the brake with the key on, shift to Neutral, and try to start the car. If it reliably starts this way, you probably have a faulty Transmission Range Sensor (TRS). If not, then you'll need to use the meter or a test light and check for the starter trigger at the starter motor. If it's not there, start tracing back toward the ignition switch. Ford has had issues with ignition switches (not the key cylinder switch, but the switch that it activates).

-Rod