Wiring stereo

Hey lads,
Tried wiring stereo, red to red and yellow to yellow, would not work.
Only way I could get it to work is by joining red and yellow together, but it is not saving settings (so yellow constant aint working!)
Any ideas why this is?
I have checked fuses and seem OK, any specific fuse I should be looking at, under bonnet or inside fuse box?
I checked with another stereo and this works correctly - red to red and yellow to yellow and saves settings!
Weird one....
Tried wiring stereo, red to red and yellow to yellow, would not work.
Only way I could get it to work is by joining red and yellow together, but it is not saving settings (so yellow constant aint working!)
Any ideas why this is?
I have checked fuses and seem OK, any specific fuse I should be looking at, under bonnet or inside fuse box?
I checked with another stereo and this works correctly - red to red and yellow to yellow and saves settings!
Weird one....