I work for the bank and you can only access your US account if it is programmed to your Primary "Chequeing" or "Savings" button.
These buttons are only place holders, so it depends where you/or your bank have placed it on your card. If your US account is attached to your "other" slot you will probably NOT be able to access your US account. (It might depend on the bank machine you’re using and if the option is even available)
Having said that, with 99.9% of bank card will allow you to take money out of your chequeing account and it will dispense it in US cash BUT there will be a exchanged difference (conversion amount from Cdn to US) and an international ATM fee - my bank charges a flat fee of $3.00 CDN.
Bottom Line:
"Chequeing" button is account #1
"Savings" button is account #2
Every other account you have access to will be listed under "other" or "additional account" and with my bank you can have up to 10 "others" (again most times can't access these outside of Canada)
The name DOESN"T identify the type of account.
Call your bank's telephone banking phone number and ask where your US account is linked on your card, get it changed IF they'll allow direct withdrawals.
Oh and if your going to take money out with your bank/debit card. Tell the bank.....so they don't cancel your card, thinking it's been stolen and been used suspiciously. You won't have access to your bank account until you go home to the bank.