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Intermittently failing to start

Hello! I have checked my Ford Taurus 2009 in for diagnostics/check-up 4 times to multiple locations for this issue, but no answers. Unexpectedly, my car will fail to start. I drive it for a while (like from work to home), park it, and I turn it off. When I try starting it, usually less than an hour after turning it off, it will not start. No clicking noises, no noises at all. Key turns. Lights come on. The battery has been replaced, oil has been changed, everything is normal and up to date. This happens anywhere from 1 to 3 times a week, usually when it is extremely hot outside. But, it always starts first thing in the morning after it’s been sitting in my garage all night. I am at a loss, and nobody else can figure it out. If you have any input on how to fix this, I would be greatly appreciative. Thanks!

The next time this happens, with the dash lights on, step on the brake pedal and shift the transmission into neutral and then try starting the engine.

If the engine starts right up, there’s a problem with the park/neutral safety switch.

https://www.rockauto.com/en/catalog/ford,2009,taurus,3.5l+v6,1443431,electrical-switch+&+relay,neutral+safety+switch+/+range+sensor,4584

Tester

1 Like

Try Tester’s idea. Also, your owners manual may say more about how to override the neutral safety switch in case it’s preventing the starter motor from working.

This is the most common problem we get here, fails to crank. Not just on the Taurus but on all cars. So you are not alone. If you can get it to the shop when this is happening they can monitor the voltages at the two connectors on the starter motor with the key in “start”. Both should measure above 10.5 volts. If not, something ahead of the starter is the problem. If both meet that voltage spec and it doesn’t crank, the problem is almost certainly the starter motor itself, and needs replacement. Once the voltage test is done, should be easy to figure it out from that. Even if it is cranking ok at the time, the voltage test might still provide a clue. My guess is the heat is preventing the starter motor from working, and the starter motor needs replacement. On some vehicles there’s supposed to be a heat shield near the starter motor. Sometimes that heat shield is removed for access to something else, and they forget to put it back.