Q: connecting 2 iphone 5c's to pioneer deh p7000bt

Hello there, bwccattleco.

It sounds like you are having an issue with one of your iPhone 5c's not connecting to your car stereo. The following Knowledge Base article offers up some great steps for troubleshooting the issue you're describing:

If you can’t use a Bluetooth accessory or car kit

http://support.apple.com/kb/HT6473

To resolve the issue, you'll need to first sign in to iCloud and review your devices:

1. Sign in to iCloud on your iOS devices.
2. On one of your devices, tap Settings > Bluetooth and look under My Devices. You'll see all devices that are connected to Bluetooth, but make sure that you see your Apple devices that are signed in to iCloud and are using iOS 8.
3. Sign out of your iCloud account from any devices that you don't want to use. To sign out of iCloud on an iOS device, tap Settings > iCloud > Sign Out.

Then, remove any inactive devices from iCloud:

1. Sign in to iCloud.com.
2. Select Find My iPhone.
3. Select any devices that aren't active anymore.
4. Wait for Find My iPhone to stop trying to find the inactive device.
5. You should see the option to remove this device from your account. Select it to remove the device.

After following the steps above, restart the device with the issue. Then try to use it with your Bluetooth accessory.

There are also some additional troubleshooting steps in this article as well:

iOS: Troubleshooting Bluetooth connections

http://support.apple.com/kb/TS4562

Thanks for reaching out to Apple Support Communities.

Cheers,

Pedro.