i have an 87 740 and am having some issues recently i had a little mishap with the fuse box fuse 16 for the heater melted along with its slot in the fuse box. the wire was very hot and melted the fuse box. i swapped out the fuse box with a new one lots of wires and added a .2 ohm 50 watt resistor with a heat sink on it to try and prevent it from happening again but it blew after about 10 min. also when that fuse is not connected the radio fuse 14,horn fuse and windshield wipersfuse 15 along with the heat do not work. anyone have any ideas ??? when the wire is connected to the fuse all work as they should. i dont have a voltmeter at my house so i cant get an actual wattage flowing through that wire but it blew up a 50 watt resistor without blowing the 15 amp fuse. Could the wires from the heat radio and wipers be crossed somewhere causing them all to flow through that one fuse??? also i am 100% sure that when i replaced the fuse box all wires are correct any help would be appriciated

 

Most of the time that happens when the blower motor goes bad.It pulls way to many amps and overheats the wiring and the fuse box.

Try unplugging the blower motor and see if the fuses still blow.

 

none of the fuses popped but all of the plastic around the fuse melted. the metal part of the fuse was still connected when the heat was off however the line was not as hot so ill try the blower motor on fri thanks guys ill let you know how it turns out