Fusible Link for alternator

[donmcgowen]

2015 Mustang GT ON3 61mm twin kit charging system light is on.
I had an issue with the power cable going to my alternator. I had to add an extension because of turbos. Anyway, the cable pulled off the alternator doing a pull. Brought it home put it on the lift and found the problem. Like a dumbass, I tried to reconnect it and ended up shorting the cable.

The problem is I don't know where the fusible link is. Does anybody know where the fusible link it? In older cars they were an extension to the battery cable that would break and you had to replace the cable. But this car it might be one of the bigger fuses in fuse box. But I checked all the fuses and they all look good.

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[boB]

The problem is I don't know where the fusible link is. Does anybody know where the fusible link it? In older cars they were an extension to the battery cable that would break and you had to replace the cable. But this car it might be one of the bigger fuses in fuse box. But I checked all the fuses and they all look good.

According to the 2019 service manual (that's all I have) there is no fusible link from the alternator, just a 275 A Mega-fuse.

 

[DickR]

I looked at the 2015 FSM and it "shows" a 275 amp "Mega" fuse "in" the battery junction box BJB). If you look in the BJB it appears that the 275 amp fuse is located where the battery cable (middle cable) connects to the BJB. FYI you might make sure that F36 which is a 10 amp fuse and F7 which is a 60 amp fuse are still OK.

I don't know how to access the 275 amp fuse but I would start with disconnecting the battery and then the nut that secures the cable to the BJB unless the new part makes replacement obvious.

Edit to add: https://www.delcity.net/store/Low-T..._APlBnSpLe_o5W5NX4-Z0Sxh4nim0LVcaAtE9EALw_wcB

It looks like MEGA fuse is a standard fuse available from auto parts stores.

Edit again: I cannot find the part on fordpartsonline but other internet info indicates it may be a specific Ford configuration.

 

[donmcgowen]

Hey guys, thanks a bunch. That is helpful because I didn't want to go on a wild goose chase. I think this should be a big help.

 

[DickR]

Hey guys, thanks a bunch. That is helpful because I didn't want to go on a wild goose chase. I think this should be a big help.

Let us know what oem or aftermarket part it requires. Fordpartsonline and "the internet" are coming up empty for the S550's. S197's have an oem assembly.

Good luck.

 

[donmcgowen]

I called Ford and told them what I needed. They are ordering the fuse. It's a 275a/125a fuse. I'm just not sure where it is in the fuse box. There are a bunch of the same big fuses. I'll have to wait until I get the part and have Ford print out the diagram of where it is. I'll post part number when I pick it up.

 

[DickR]

Thanks! Based on pics of the similar S197 part and looking at mine I'm 95% sure it will be a "slide/snap" out and in assembly in the fuse box (BJB) where the red wires from the battery, etc. connect. On my 18 "275" and "125" are stamped in the metal adjacent to the wire connectors.

 

[boB]

I called Ford and told them what I needed. They are ordering the fuse. It's a 275a/125a fuse. I'm just not sure where it is in the fuse box. There are a bunch of the same big fuses. I'll have to wait until I get the part and have Ford print out the diagram of where it is. I'll post part number when I pick it up.

Interesting, I have never seen a fuse with two current ratings. The service manual shows a 275 A for the alternator and a 125 A (sharing a common feed with the 275 ?) for the power steering.

 

[DickR]

Interesting, I have never seen a fuse with two current ratings, looks like it may be one big fuse that protects two separate circuits. The service manual shows a 275 A for the alternator and a 125 A (sharing a common feed with the 275 ?) for the power steering.

It is two separate fuses but sold as an assembly. MEGA 275 for the alternator circuit and MIDI 125 for the electric power steering.

 

[donmcgowen]

Thanks guys. Can one of you with the service manual, can you email me pics of where the fuse is? Without seeing what it looks like I'm not sure where it is. If someone can snap a couple pics from the manual that would be awesome.

Please send to [email protected]

Thanks again
Don

 

[DickR]

The fuse and fuseholder assembly is probably at the top right of the photo. I'm pretty sure the red wires connect to the fuseholder.

The pics and the FSM pic are probably from my 2015 and from the 2015 FSM. However, the 2018 I have now looks the same.

What I haven't figured out is how the fuseholder assembly is secured once the wires are disconnected. My guess is a snap fit using what appears to be a "tab".

FYI the red jumper wire at the bottom left of the picture replaces the relay which is used to turn off power to the console power points (cigarette lighter). My data acquisition system uses the one in the console and I don't want it timing out when the engine isn't running.

 

[donmcgowen]

Dick R, so you are thinking the fuse is under the power cable. From your Pic, the power cable at the top right is the one that doesn't have power. I have disconnected them previously because I moved my fuse box for turbo install, and I don't remember anything under them. But, Ill check when I get home. I'm thinking that once I get the new one from Ford and know what it looks like I should be able to find it.

 

[DickR]

Dick R, so you are thinking the fuse is under the power cable. From your Pic, the power cable at the top right is the one that doesn't have power. I have disconnected them previously because I moved my fuse box for turbo install, and I don't remember anything under them. But, Ill check when I get home. I'm thinking that once I get the new one from Ford and know what it looks like I should be able to find it.

Per the 2015 FSM battery + connects to C1035A which is the recessed terminal on the left of the three. Alternator input is C1035B which is the middle terminal. Power steering is C1035C.

I think you should have power on C1035A but not on C1035B if the 275 amp MEGA fuse is blown or on C1035C if the 125 amp MIDI fuse is blown.

EDIT to add: I would also check the smaller fuses I mentioned in a previous post.

 

[donmcgowen]

Per the 2015 FSM battery + connects to C1035A which is the recessed terminal on the left of the three. Alternator input is C1035B which is the middle terminal. Power steering is C1035C.

I think you should have power on C1035A but not on C1035B if the 275 amp MEGA fuse is blown or on C1035C if the 125 amp MIDI fuse is blown.

EDIT to add: I would also check the smaller fuses I mentioned in a previous post.

Thanks man, this is so helpful. So to clarify, the recessed power is from the battery. Then the other two are alternator and power steering?

I'll test again tonight, but last time it was the outer post that didn't have power. I wo Der if I have the power cables swapped in the fuse box. Wish the diagrams were more what it really looks like, but I think I got it.

I'll wait until I get the new fuse to see where it goes exactly.

 

[DickR]

That is what the FSM wiring diagram indicates. I just looked at my 2018. The three cables are different sizes. The middle cable (connected to the 275 amp terminal) is the biggest. The smallest cable is connected to the 125 amp terminal and the medium cable is connected to the recessed terminal which is supposed to go to the battery. The middle cable goes through the "ring" which I believe is for the current sensor.

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