Normal for stereo to restart when car started?

[Clarkey]

I would guess only really cars with start/stop technology would go to efforts to avoid this. Every non start/stop car I've had has done this, you generally lose all accessory power during cranking.

 

[adolf hamster]

I swapped the cables and the same thing happens. The cigarette lighter power also goes off so I'm assuming it's just a normal feature of the Mazda2.

if the stock radio did it then yep, and it wouldn't be that surprising tbh

 

[badgeruk]

My ibiza's did this but both Z4's don't unless I haven't driven them for a while. Both stock/custom radios.

 

[agw_01]

Nothing to do with shoddy old cars or power drain caused by the starter.

Radio/blower/windows are provided power when the key is in the accessory/ignition position. You turn the key to the start position, which moves it away from these positions. The connections are broken. The engine starts and you release the key which returns to the ignition position and power is restored. It's designed to work this way. If you supplied a permanent 12v to these feeds, the radio and windows would still work when you turned the key to start.

 

[Rroff]

Hah I'd overlooked that.

 

[MatteH Oxford]

What about systems such as keyless ignition, which have may a fault if the accessory power isn't cut during cranking?. I'd presume there is some sort of relay (possibly transistor controlled) that should provide this function due to the lack of a physical connection at the ignition switch?.

 

[agw_01]

Hah I'd overlooked that.

Just one of those you get in and do without thinking about how it works. I guess you have to be a real saddo (like me ) to actually analyse it, haha.

 

[Rroff]

Just one of those you get in and do without thinking about how it works. I guess you have to be a real saddo (like me ) to actually analyse it, haha.

I work with those kind of switches (not automotive use) quite a bit - it really should have occurred to me.