Samsung phone finds Bluetooth but pairing always fails

I couldn't find an user guide for your headset. So, here come my suggestions: first, try '0000' (four zeros), which happens to be the most commonly passkey chosen by all manufactures. If this code fails, then try '1234'. If that fails, try '8888'.
Hope one of these passcodes works for you.

That usually means it isin pairing mode. Charging some headsets from extended periods can sometimes reset the device requiring you to pair the device again.

with your phone STILL ON remove the battery, wait 5-10 seconds replace battery..power up phone and try to pair. should work after phone resets itself.

headset won't pair with me phone and i have tried 0000 and 1234 and 12345

0000

Bluetooth headsets are the most common cell phone accessory and quickly have become a common sight when out in public. Everyone from teenagers to businessmen are wearing bluetooth headsets, seemingly talking to themselves, and carrying on in their day-to-day lives. Over the last two years, the popularity of bluetooth has made wireless communication a part of everyone's lives and while owning a headset used to be out of the price range of many cell phone users, that is no longer the case. Now, more than ever, cell phone users everywhere are investing in bluetooth headsets and using them when making and taking calls.

Canadian Tire's HFBLU-LT100 (BK-600) won't connect to my SPH-m300 Samsung phone but I entry of the passcode (0000) about 20 times before it connect successfully.

For Cellular Innovations Mini Blue HFBLU-AX1C.
To Pair with Your Phone....

1. Turn OFF Bluetooth Headset
2. With Headset within 1 Ft of your phone, hold down power key for about 8 seconds until indicator light blinks in red and blue color quickly (in pairing mode)
3. Search bluetooth device through your mobile phone.
4. Select HFBLU-AX1C in the bluetooth device list and enter the password 1234.

For Cellular Innovations Mini Blue HFBLU-AX1C.
To Pair with Your Phone....

1. Turn OFF Bluetooth Headset
2. With Headset within 1 Ft of your phone, hold down power key for about 8 seconds until indicator light blinks in red and blue color quickly (in pairing mode)
3. Search bluetooth device through your mobile phone.
4. Select HFBLU-AX1C in the bluetooth device list and enter the password 1234.

when you pair them up have them about a foot apart they can be a bit temprimental but they do pair up.