# What is an electrical safety switch? **URL:** \ **Category:** Factual Questions\ **Created:** [April 3, 2009, 4:50pm UTC](https://boards.straightdope.com/t/what-is-an-electrical-safety-switch/491885 "2009-04-03T16:50:02Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Pseudocode](https://avatars.discourse-cdn.com/v4/letter/p/59ef9b/32.png) [@Pseudocode](https://boards.straightdope.com/u/Pseudocode)\ **Post date:** [April 3, 2009, 4:50pm UTC](https://boards.straightdope.com/t/what-is-an-electrical-safety-switch/491885/1 "2009-04-03T16:50:02Z")
I have a 1989 Dodge Dynasty in the shop right now (it wouldn’t start). They said the problem was the electrical safety switch. What are they talking about? ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [April 3, 2009, 5:14pm UTC](https://boards.straightdope.com/t/what-is-an-electrical-safety-switch/491885/2 "2009-04-03T17:14:15Z")
Probably the “Neutral Safety Switch.” It prevents the car from starting unless the transmission is in Neutral or Park. ---
**Author:** ![OldGuy](https://avatars.discourse-cdn.com/v4/letter/o/3bc359/32.png) [@OldGuy](https://boards.straightdope.com/u/OldGuy)\ **Post date:** [April 3, 2009, 5:15pm UTC](https://boards.straightdope.com/t/what-is-an-electrical-safety-switch/491885/3 "2009-04-03T17:15:41Z")
> [@beowulff](#): > > Probably the “Neutral Safety Switch.” > It prevents the car from starting unless the transmission is in Neutral or Park. Never mind – answer edited ---
**Author:** ![Pseudocode](https://avatars.discourse-cdn.com/v4/letter/p/59ef9b/32.png) [@Pseudocode](https://boards.straightdope.com/u/Pseudocode)\ **Post date:** [April 3, 2009, 5:30pm UTC](https://boards.straightdope.com/t/what-is-an-electrical-safety-switch/491885/4 "2009-04-03T17:30:25Z")
Thanks for the quick response. I also had problems with the car stalling at stoplights. Would a bad neutral safety switch be the cause of this as well? ---
**Author:** ![SpectBrain](https://avatars.discourse-cdn.com/v4/letter/s/a87d85/32.png) [@SpectBrain](https://boards.straightdope.com/u/SpectBrain)\ **Post date:** [April 3, 2009, 6:24pm UTC](https://boards.straightdope.com/t/what-is-an-electrical-safety-switch/491885/5 "2009-04-03T18:24:46Z")
On some cars there is also an inertial fuel pump switch (cuts off fuel in case of an accident) but could be tripped after a hard bump. [http://www.coolcats.net/tech/troubleshooting/inertia.html](http://www.coolcats.net/tech/troubleshooting/inertia.html) ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [April 3, 2009, 8:08pm UTC](https://boards.straightdope.com/t/what-is-an-electrical-safety-switch/491885/6 "2009-04-03T20:08:36Z")
> [@Pseudocode](#): > > Thanks for the quick response. > > I also had problems with the car stalling at stoplights. Would a bad neutral safety switch be the cause of this as well? No. The NSS is a starter interlock, but it doesn’t prevent the engine from running- if it did, the car would stall when you put it in Neutral or Park. ---
**Author:** ![Gary\_T](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@Gary\_T](https://boards.straightdope.com/u/Gary_T)\ **Post date:** [April 3, 2009, 8:32pm UTC](https://boards.straightdope.com/t/what-is-an-electrical-safety-switch/491885/7 "2009-04-03T20:32:17Z")
“Won’t start” covers a lot of ground. If the starter wouldn’t crank, it was probably a neutral safety switch. If it would crank but not catch and run, it could have been a fuel pump inertia switch. Neither of these would cause stalling at stops (I assume it would restart immediately). That’s a separate issue. ---
**Author:** ![Pseudocode](https://avatars.discourse-cdn.com/v4/letter/p/59ef9b/32.png) [@Pseudocode](https://boards.straightdope.com/u/Pseudocode)\ **Post date:** [April 3, 2009, 9:48pm UTC](https://boards.straightdope.com/t/what-is-an-electrical-safety-switch/491885/8 "2009-04-03T21:48:12Z")
The starter would crank a few times, but the engine wouldn’t start. (I’ve had problems where the engine starts but immediately dies unless I give it some gas, if that is relevant.) If it didn’t start within a few tries, it would stop cranking and turning the ignition would give absolutely no response. If I had some sort of fuel line problem that was causing the stalling, I would be fine with it as long as I could just restart the car again, since I’m going to get a new car soon. However, when it does stall, I am much more likely to have difficulty starting it again.