Help with replacement wireing harness, possibly defective

   / Help with replacement wireing harness, possibly defective #1  

petebert

Silver Member
Joined
Oct 12, 2011
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223
Location
Outside of Ann Arbor
Tractor
...
I went online looking for a replacement wiring harness. They seem to range from $25 to $250. I decided on this one Wiring Harness, Front | Ford | C9NN14A13B because it was listed as being for one with an alternator and my tractor (Ford 335 or 3600) has been converted to an alternator instead of a generator.

To start I'll go with the most important question because I think this harness might be defective. I should have 3 constant hots right? One to ignition, one to alternator and one at the starter getting power from the battery. I can only find two which makes me think there's a missing connection in this harness.

Now on to the rest of the harness. I'm wondering if this harness is setup correctly so I know whether to ask for a replacement or just a refund if it is defective.

Here you can see the ignition and gauge bundle. The red wire at the bottom has an eyelet and I believe it's the alternator wire. It has another wire bundled with it, no idea where that would go, it doesn't quite reach the oil pressure or temp sender. For my testing I stuck the red wire with the eyelet on the hot starter post, I was able to get voltage at the large red ignition wire but no other wire in the entire bundle went hot.

vLKgBEM.jpg


When the key is moved to the spring loaded position voltage did go to this large green wire, marked A. It was just a guess on my part that, that wire would be to activate the starter since it was in the ignition bundle and large, probably 10 gauge. No other green wire received voltage in this position.

QG46SYr.jpg


Also in the ignition bundle are a smaller green and a green/white. There's a few greens and green/whites throughout this harness but only two receive voltage when the ones at the ignition are activated. I'm guessing they are gauge cluster and light switch supply although they're too close to each to reach both without cutting the wrapping. These two are circled here.

JHYe7jU.jpg


Here's an overall view. The green and green/white(accessory?) are to the far left, the green that I believe is to activate the starter is to the far right. I believe the constant hot source for the starter should also be in one of those groupings on the right side.

XqizPsH.jpg
 
   / Help with replacement wireing harness, possibly defective #2  
There should be 2 constant hot wires. The one to the ignition switch is the same wire that goes to the starter, it gets it's power from the starter and takes the power to the switch. I have a couple wiring diagrams I could send you, they are for other models but may similar enough.
 
   / Help with replacement wireing harness, possibly defective
  • Thread Starter
#3  
I have the actual wiring diagram for this tractor. The constant hot needs 3 ends, it feeds from the giant connection at the starter that is bolted on. One line goes to the alternator for the charge, the other to the ignition switch.

I ended up sitting down with a battery and putting power onto each line individually and figuring out what went where. The harness really didn't make any sense. It kind of resembled what it should look like but it seems like they just put a bunch of random wires in there. They wrapped it nicely and made it look like a nice product but it wasn't very functional, so I just made my own harness. The wiring for this tractor is really simple.

The one thing I'm wondering is... during charging you're looking at 14 volts. Without a voltage regulator it's going to be sending 14 volts through the entire system. Are the lights and gauges going to be okay with the extra voltage?
 
   / Help with replacement wireing harness, possibly defective #4  
That is a normal charge rate. I was saying 2 hot because the one on the starter is the feed. 14.2 is considered the max normal charge for a 12v system.
 

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