Rim Blow wheel, weak horn

[440forPOWER]

Just added a reproduction rim blow wheel to my 70 Challenger. And the horn is really weak. I don't remember ever trying the horn with the factory wheel. So I'm not sure if the new wheel has anything to do with it. Could this be a bad horn relay? Or has anyone ran into the same issue? Thanks in advance

 

[cuda joe]

could be a bad horn run a wire from the battery to the horn and see if it;s louder .i have seen old horns come back to life by powering them up for a few minutes