# AC Switch On At Engine Start? **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** nissan, frontier\ **Created:** [October 21, 2009, 5:43pm UTC](https://community.cartalk.com/t/ac-switch-on-at-engine-start/38416 "2009-10-21T17:43:44Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![PitterCol](https://avatars.discourse-cdn.com/v4/letter/p/5fc32e/32.png) [@PitterCol](https://community.cartalk.com/u/PitterCol)\ **Post date:** [October 21, 2009, 5:43pm UTC](https://community.cartalk.com/t/ac-switch-on-at-engine-start/38416/1 "2009-10-21T17:43:44Z")
Is it bad to have the AC switch “on” when starting the motor? ---
**Author:** ![lenjack](https://avatars.discourse-cdn.com/v4/letter/l/f475e1/32.png) [@lenjack](https://community.cartalk.com/u/lenjack)\ **Post date:** [October 21, 2009, 6:16pm UTC](https://community.cartalk.com/t/ac-switch-on-at-engine-start/38416/2 "2009-10-21T18:16:24Z")
No harm. Modern vehicles will delay the AC start till after the engine has started. ---
**Author:** ![mcparadise](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mcparadise/32/32_2.png) [@mcparadise](https://community.cartalk.com/u/mcparadise)\ **Post date:** [October 21, 2009, 6:18pm UTC](https://community.cartalk.com/t/ac-switch-on-at-engine-start/38416/3 "2009-10-21T18:18:27Z")
No. It won’t hurt anything. The compressor won’t engage until after the engine is running. ---
**Author:** ![Beadsandbeads](https://avatars.discourse-cdn.com/v4/letter/b/c57346/32.png) [@Beadsandbeads](https://community.cartalk.com/u/Beadsandbeads)\ **Post date:** [October 21, 2009, 6:32pm UTC](https://community.cartalk.com/t/ac-switch-on-at-engine-start/38416/4 "2009-10-21T18:32:43Z")
It might not hurt the engine, but it hurts me to have the accessories going with I am starting the engine. If the blower is on high and the radio loud, I can’t tell when to stop cranking the starter. It is very annoying. I like to hear the first explosions of gasoline and air unmasked by the sound of the AC compressor as well. ---
**Author:** ![tardis](https://avatars.discourse-cdn.com/v4/letter/t/f0a364/32.png) [@tardis](https://community.cartalk.com/u/tardis)\ **Post date:** [October 21, 2009, 7:01pm UTC](https://community.cartalk.com/t/ac-switch-on-at-engine-start/38416/5 "2009-10-21T19:01:22Z")
That’s funny. On all the cars I have or have ever had or driven, The blower, radio, and AC compressor don’t operate while the ignition switch is in the start position. They come after the switch is released, which you would do because you heard the engine start to run, or because you had held it the amount of time it normally takes to start it. It’s your car, and you should operate it the way you want to, but your justification does not ring true. ---
**Author:** ![DoctorPinto](https://avatars.discourse-cdn.com/v4/letter/d/b19c9b/32.png) [@DoctorPinto](https://community.cartalk.com/u/DoctorPinto)\ **Post date:** [October 21, 2009, 7:39pm UTC](https://community.cartalk.com/t/ac-switch-on-at-engine-start/38416/6 "2009-10-21T19:39:00Z")
Same here, except when I owned my VW Jetta POS. The factory radio was wired hot…it doesn’t shut off with the key. I believe most VWs are like that. ---
**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\ **Post date:** [October 21, 2009, 11:03pm UTC](https://community.cartalk.com/t/ac-switch-on-at-engine-start/38416/7 "2009-10-21T23:03:11Z")
Right. The AC compressor relay circuit is not energized with the key in the “start” position. On my '61 Beetle (which I owned in the late '60s) the radio wouldn’t even go off by itself after the key was removed. I needed to turn it off seperately. Needless to say, it did not have AC. It barely had heat. ---
**Author:** ![Beadsandbeads](https://avatars.discourse-cdn.com/v4/letter/b/c57346/32.png) [@Beadsandbeads](https://community.cartalk.com/u/Beadsandbeads)\ **Post date:** [October 21, 2009, 11:09pm UTC](https://community.cartalk.com/t/ac-switch-on-at-engine-start/38416/8 "2009-10-21T23:09:42Z")
You are correct, of course, but I still hate it. ---
**Author:** ![DoctorPinto](https://avatars.discourse-cdn.com/v4/letter/d/b19c9b/32.png) [@DoctorPinto](https://community.cartalk.com/u/DoctorPinto)\ **Post date:** [October 21, 2009, 11:38pm UTC](https://community.cartalk.com/t/ac-switch-on-at-engine-start/38416/9 "2009-10-21T23:38:11Z")
Now THAT sounds like something my future ex girlfriend tells me all the time…