I have a d4c rainbow vacuum, need help replacing the electrical cord

There is no reset button, but some of those old switches are very touchy . . . if there was some  corrosion, you may not have a good contact (was enough of the new wire insulation stripped away, before putting it into the switch) . . . 
I prefer splicing, rather than going all the way to the switch  . . its just a matter of cutting out the old cord and splicing in the new cord in a convenient spot up in the motor compartment. . . a Rainbow purist would run the new cord all the way up into the power on/off rocker switch that's built into the top of the handle and then wire the new cord in there, directly at the switch . . . that way means no splicing . . . I've done it both ways, but I prefer to splice and use wire connectors inside the motor compartment . . . because going further, all the way up directly into the on/off switch just to avoid splicing the new cord in requires taking more things apart . . . and risks screwing up the power switch . . . that's not worth the extra time and trouble, IMHO.  (This from someone who has dismantled and refurbished over 200 D4C and SE models)

FYI, there is a good chance that when you used that rainbow standard issue safty pin , u may have damaged the switch internally, or your connections are not making good contact.................good luck.......ps do you have power at the receptical where you plugged in your cord?........check it..........