Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum - View Single Post - 75 amp fusible one side to ground with alternator and battery disconnected

S13ORLANDO · 10-08-2012, 08:46 AM

This was happening with the original lower harness too. Here is the original symptoms. Driving early morning second week of June. All gauge lights,radio,rear tail lights go out. Engine runs okay,headlights okay. Daylight later that day, the wires on the output of the alternator are burned up. I repaired them,discovered 75 amp fusible link blown. Long story short,blew same 75 amp fusible link. I got my trusty FLUKE and the FSM. I find a short to ground on the 75 amp. I begin to suspect my lower harness. I found a lower harness from FRSPORT. There is no way I 'm SMOKIN THAT LINK AGAIN!

I'm testing everything first. So before I plug in the alternator or anything else I am ohming out everything. I plug that one rectangular plug below the passenger side box for the fusible links.
. I am concentrating on that 75 amp fusible link. With the 75amp fuse out. One side ohms good to the positive side of the main battery. The other goes straight to ground once the cable is plugged. I looked at the bottom of the fusible link holder. I wanted to see if one of those two white wires was chaffing or broken insulation.

I followed the harness downstream..runs along the radiator and down into the drivers side box under the hood.

Help me with some LOGIC. They has to be a way to ISOLATE WHICH SEGMENT IS HOSED ? My worst fear is that this is a CHAFFED wire under a body panel or

REAR of the car. How do I BREAK this into SEGMENTS for TROUBLESHOOTING ? ?

10-08-2012, 08:46 AM	#2
S13ORLANDO Leaky Injector Join Date: Aug 2002 Location: Orlando,Fl Age: 66 Posts: 63 Trader Rating: (0)	Best I can figure, One side (not battery side) of 75 amp fusible link is grounded This was happening with the original lower harness too. Here is the original symptoms. Driving early morning second week of June. All gauge lights,radio,rear tail lights go out. Engine runs okay,headlights okay. Daylight later that day, the wires on the output of the alternator are burned up. I repaired them,discovered 75 amp fusible link blown. Long story short,blew same 75 amp fusible link. I got my trusty FLUKE and the FSM. I find a short to ground on the 75 amp. I begin to suspect my lower harness. I found a lower harness from FRSPORT. There is no way I 'm SMOKIN THAT LINK AGAIN! I'm testing everything first. So before I plug in the alternator or anything else I am ohming out everything. I plug that one rectangular plug below the passenger side box for the fusible links. . I am concentrating on that 75 amp fusible link. With the 75amp fuse out. One side ohms good to the positive side of the main battery. The other goes straight to ground once the cable is plugged. I looked at the bottom of the fusible link holder. I wanted to see if one of those two white wires was chaffing or broken insulation. I followed the harness downstream..runs along the radiator and down into the drivers side box under the hood. Help me with some LOGIC. They has to be a way to ISOLATE WHICH SEGMENT IS HOSED ? My worst fear is that this is a CHAFFED wire under a body panel or REAR of the car. How do I BREAK this into SEGMENTS for TROUBLESHOOTING ? ?