95 Riviera alarm/key problems

Had the heater radiator replaced at a rad. shop. In the process they disconnected battery to prevent accidental air bag deployment.
After replacement I got car back, but on the way home the horn came on all the time under any condition, also key no longer unlocks doors. Remote still controls doors. Stereo, CD all work fine. Finally had to pull horn relay, which by the way tested OK.
Seems like security problem, maybe....
Would appreciate any suggestions on how to fix left over present from radiator shop.