don't use to big a fuse in the holder. we have been having some trouble with the AC in the 72 cb. it has the comfortron automatic system in it and to say that it's qurkie is a understatement. any way searched around till I found the main vacuum leak to get the controls to work properly. then the intermittent problem with the fan became a permanent problem. so under the hood we go. all the relays were working so we checked the power wire. I remember when I got the car it has a inline fuse that the holder had melted . I did replace it but only had a fuse to small for the blower so I put in this 30 amp. I knew the motor would never trip it. I was right. looks like the holder was not rated at the amperage the motor will draw. it has started arcing on the far side and kept it up till it melted the blade on the fuse. the fuse never blew. as long as the leg was making connection with it's melted part it would come on. . needless to say we went down a bought a holder that would carry the load and removed the quick disconnect in line also. after all every connection is a resister. then put in the proper 25 amp fuse. now we have air and air movement.