Air Conditioning - Hi Guys, thermostat wiring ??...Help Please!!!!!

:wall: Hope you can help, so I don't have to call professionals who are better qualified than I !!! I have a single stage ac/ with gas heat ..I see carrier and goodman on the stacked units in my closet. The outside fan thing says carrier also.
I am trying to replace a White-Rodgers IF86-244 (non programable), with a Honeywell programmable RTH 7400. This is the only brand Home Depot had.
The 4 wires on the White were W G Y B and B had a connector between B and RC.
I connected them the same on the Honeywell, except the b went to c per instructions. There is also a connector between the R and Rc on the Honeywell. Nothing works at all on the honeywell with this config, no fan, no cool nothing. I did the setup thing also. I reconnected my old tstat, and it works fine, so i know i didn't mix up the wires...It has to be somethng with that B or the connector on the r's....Please help, if I need to take pictures of it I will......Thanks for any help in advance!

and what would happen if i try the B wire in some of the other
places? Could it hurt it? I feel like B is really an R wire...help! and I am not sure what sinle stage means...so i may NOT have that..its just gas heat and elec a.c....Thanks again!

Yes, the "B" wire should connect to the R and Rc connections on the new thermostat.