Electrical Need help with alternator yellow wire

Busa1300 · Mar 1, 2021

I just put the 130 amp SVE alternator on my car because I was told my factory one was bad. Well when I got it installed it still wasn't charging. After looking at wire diagrams I checked the yellow wire coming of the plug from the alternator. According to the diagram the yellow wire should be my hit wire. Well it has nothing to it. I also see the yellow wire has a fusible link on it. So starting at the alternator I am tracing the yellow wire back to towards the battery. And I am to the drivers side fender and I still haven't found a fusible link or seen where the wire goes too. Where is it getting the power from?

mikestang63 · Mar 2, 2021

Do NOT follow the wiring instructions from LMR.
Do NOT reattach the factory power wires. Tape them up and tuck them away
Only reattach the stator signal wire from that plug to the male stator connection on the 3G
Use the 4 gauge power wire with a 150-175 amp in line fuse and connect one end to the power terminal on the 3 G alternator and the other end to the hot side of the starter solenoid where the battery cable attaches. Route it around the front of the car in front/on top of the radiator
Connect the factory D shaped wiring to the 3 G alternator

Done

evintho · Mar 2, 2021

The other end of your YEL wire ties into the fusible link wire, which I believe is BRN then GRN which attaches to the POS side of your starter solenoid, on the inner fender panel. Here's a pic of alt wiring removed.....

And, mikestang63 is correct. Dump the 2 BLK/ORG wires and replace with a 4ga cable and 175a fuse. Both the 4ga and your YEL wire attach to the same + post on the solenoid.

Busa1300 · Mar 2, 2021

Ok I will take off the orange/black wires from the alternator. I already have the 4 gauge wire ran over to the solenoid. All that is good and hot. The yellow wire on the D shape plug is not hot. That is the wire I am tracing on the drivers side fender. I am hoping it is the fuseable link. Which I can't find either. When I get some better weather I am going to take off the inner fender well on the driver's side. And I am hoping then I can find the yellow wire and the fuse link. Thanks for the info on the orange/black wire

mikestang63 said:
Do NOT follow the wiring instructions from LMR.
Do NOT reattach the factory power wires. Tape them up and tuck them away
Only reattach the stator signal wire from that plug to the male stator connection on the 3G
Use the 4 gauge power wire with a 150-175 amp in line fuse and connect one end to the power terminal on the 3 G alternator and the other end to the hot side of the starter solenoid where the battery cable attaches. Route it around the front of the car in front/on top of the radiator
Connect the factory D shaped wiring to the 3 G alternator

evintho said:
The other end of your YEL wire ties into the fusible link wire, which I believe is BRN then GRN which attaches to the POS side of your starter solenoid, on the inner fender panel. Here's a pic of alt wiring removed.....

And, mikestang63 is correct. Dump the 2 BLK/ORG wires and replace with a 4ga cable and 175a fuse. Both the 4ga and your YEL wire attach to the same + post on the solenoid.

Where does that brown wire go too? The D shape plug also? If I cut the fuse link off the yellow wire can I put an in line fuse on it and attach it to the solenoid?

evintho · Mar 3, 2021

The YEL wire connects to the BRN wire, which ties into the BLK/ORG wire, which connects to the GRN wire, which is the fusible link that connects to the POS side of the solenoid. Wow, that was confusing! Look closely at the photo and you'll see what I mean. Simply cut the YEL wire 1/4" before it connects to the BRN wire. Next, cut the GRN wire just after the splice. That will eliminate the BRN and BLK/ORG wires along with the plug completely. Finally, connect the YEL wire with a butt connector directly to the GRN wire (fusible link) and attach that to the POS side of the solenoid. You're done.

Blown88GT · Mar 4, 2021

1988 Mustang Electrical & Vacuum Troubleshooting Guide (EVTM)

File is too large to upload. Here is link to it on my Google Drive. View: https://drive.google.com/open?id=1on5czXKmpETzxUggWTGtoUuVkJT2UUxN

www.stangnet.com

p.12a

Busa1300 · Mar 4, 2021

Blown88GT said:
1988 Mustang Electrical & Vacuum Troubleshooting Guide (EVTM)

File is too large to upload. Here is link to it on my Google Drive. View: https://drive.google.com/open?id=1on5czXKmpETzxUggWTGtoUuVkJT2UUxN

www.stangnet.com

p.12a

So now we're I am confused is the instructions said to hook the old orange and black supply wires back up. Along with the new 4 gauge power wire. But I have seen people saying to not hook up the old org/blk power wires. Just the new wire. And these instructions say to NOT remove the org/blk wires

RekeHavoc · Mar 5, 2021

LMR should know better. Do not hook up the factory orange/black charge wires. Simply tape them up and stuff them back in your harness. You can't remove them completely. If you hook those up along with the new 4 gauge wire and your 4 gauge wire should happen to pop the fuse at some point, you are going to overload the factory charge wires in short order.

Busa1300 · Mar 5, 2021

Thank you to everyone's help. I found the issue. And it was the yellow supply wire burnt up. I put a new fusable link in and it is working great. I attached a photo of the problem wire.

jrichker · Mar 5, 2021

RekeHavoc said:
LMR should know better. Do not hook up the factory orange/black charge wires. Simply tape them up and stuff them back in your harness. You can't remove them completely. If you hook those up along with the new 4 gauge wire and your 4 gauge wire should happen to pop the fuse at some point, you are going to overload the factory charge wires in short order.

I posted that complaint once before and never got a reply from them. It will take a lawsuit to make them change their documentation.

As to why you don't use the Factory orange/black charge wires in addition, here's the answer:

Here is the reasoning behind using only a single 4 gauge fused power feed to the alternator. If you use the two 10 gauge black/orange wires in addition to the 4 gauge wire, you have two fused power feed paths. The total current capacity of the wiring is the sum of the fused paths. The 4 gauge path is fused for 125 amps, and the two 10 gages wires are fused for 60 amps. That is a total of 185 amps, which exceeds the capacity of the alternator. Overload can occur without the fuses blowing, damaging the alternator.

The worst case scenario is that the alternator develops an internal short to ground resulting in a catastrophic failure. The initial short circuit surge current is limited by the resistance of the wiring. The current in a parallel circuit divides up according to the resistance of the branches. If the 4 gauge fuse opens up first, the two 10 gauge black/orange wires will be carrying the short circuit surge current. Depending on the time lag of the fuse links, they may open up before a fire starts or they may not.

Busa1300 · Mar 6, 2021

jrichker said:
I posted that complaint once before and never got a reply from them. It will take a lawsuit to make them change their documentation.

As to why you don't use the Factory orange/black charge wires in addition, here's the answer:

Here is the reasoning behind using only a single 4 gauge fused power feed to the alternator. If you use the two 10 gauge black/orange wires in addition to the 4 gauge wire, you have two fused power feed paths. The total current capacity of the wiring is the sum of the fused paths. The 4 gauge path is fused for 125 amps, and the two 10 gages wires are fused for 60 amps. That is a total of 185 amps, which exceeds the capacity of the alternator. Overload can occur without the fuses blowing, damaging the alternator.

The worst case scenario is that the alternator develops an internal short to ground resulting in a catastrophic failure. The initial short circuit surge current is limited by the resistance of the wiring. The current in a parallel circuit divides up according to the resistance of the branches. If the 4 gauge fuse opens up first, the two 10 gauge black/orange wires will be carrying the short circuit surge current. Depending on the time lag of the fuse links, they may open up before a fire starts or they may not.

Yea that makes sense. I went ahead and removed the org/blk wires and everything works great. Thank you for the explanation.

Electrical Need help with alternator yellow wire

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