So im using the 3.4 alternator and originally had the 3.4 alt plug that is routed in the battery harness plugged into the back of it along with the white wire connected to positive terminal. I replaced the alt with a new one and got a new battery. Im still running into the same problem. Its not recharging the battery. So the 3.0 harness alt plug....I tried that plugged into the 3.4 alt and still not charging. What have you guys done to fix the charging problem. Pics PLEASE if you have them. Thank you

 

I strip the 3.4 alternator harness out of the battery harness, cut the plug off for the alternator, toss the remaining wires aside, splice that plug onto the stock 3.0 wiring in the truck already(just matched color for color), route the charge wire( the large white one) over to the battery(but I upgrade the wire........8 gauge is about perfect).

Never a charging issue.

Has yours ever worked or is this a recent issue?

 

This is a new issue. I just finished my swap. And it runs awsome. So much power over my old 83' 22r. Gotta love that 3.4! Anyway this is the 3.0 alt plug that is routed along side the drivers fender right ? And also curious what this 4 wire square plug is that is in the 3.4 battery harness. Thanks

 

Thanks man. I did excactly what you said and it works perfect now. Just for giggles here is my truck. 93' SAS 3.4 Swap. Thanks to yotatech and everyone for the threads and help!

 

Sounds like you got it but just for future searches.......yes pic1 is alternator harness. Just match colors to your 3.4 alternator. Pic2 is that starter relay harness.

 

Needs paint but you get the picture

 

I'm confused here. The alt charging wire goes through the fuse box with the 3.0 set up. It draws current from the Battery wire from the battery through the fuse box connections right? Will it still charge the battery this way, Or, should I just wire it up to the battery pos post directly like you said.......with a fuse of course?
? I can just cut the charging wire from where it goes back the the fuse box from the loom that goes over to the fuse box?
Wiring theory is not my friend.

 

We know !!

As long as the wire coming off the B terminal of the alternator has a path to the battery of sufficient size.

Because the battery and Alternator are on the left side it was easier for me to run the wire direct to the battery .

from the battery to the original location on the fuse block.

both wires having suitable protection .

To make it simple

 

If I remember correctly, the stock 3.0 wiring has a large garuge (thick) wire that goes from the alt, along the front of the radiator to the fuse box, then there's another large gauge wire from the fuse box to the battery positive post. All three of those points (alt, fuse box, and battery post) are at the exact same potential (voltage) at all times regardless of routing (alt -> fuse box -> battery is the exact same as alt -> battery -> fuse box). The only way those three points would be at different potentials is if there is any voltage loss due to excessive resistance in the wiring; which is why they are large gauge wires.

On the stock set up, the battery and fuse box were close enough to each other that it didn't matter how the wiring was routed. It's a given that the fuse box and battery are connected, the question would be where to attach the alt charging cable, and, again, the battery and fuse box are close enough that it doesn't matter where it attaches.

Now on a 3.4 swap you're moving the battery to the opposite side of the engine bay away from the fuse box and close to the alt. Does it make sense to route wires (and the electricity that flows through them) from the alt, across the radiator, to the fuse box, then back across the radiator (through a different wire) to the battery? Not to me, so, I wired mine: alt -> 160A fuse (in external fuse holder) -> battery -> fuse box, making sure to use new, over-sized wire (8 gauge, like dntsdad suggested) wherever possible.

Does that make sense or did I answer a question you didn't ask?

 

Yeah thanks Wyoming and Wallace. That makes sense now. In so many threads I noted that there was the big wire going to the fuse box, but nothing from the ALT to fuse to Batt then Batt wire to Fuse to fuse box. It makes sense to me though. Sac, what do you recommend for a 160 amp fuse. With an 8ga, isn't that overkill? I am going to run 4ga as I picked up 25 feet for 10 bucks at a garage sale. I understand that 120 amp would be perfect for 4ga. Can you explain the importance of a 160 amp fuse so I understand it correctly? Thanks again guys. Alt to fuse to batt...batt to 120 amp fuse to fuse box here I come.