Wiring Quandary

[Swailsd]

Straight into PDM #16 spot. No relay needed.

Thanks, that’s one connection I can mark off the list

 

[DirtDonk]

Remember, though, if you start adding more switched accessories to the PDM, that put an extra load on that one wire and the switch, you should consider adding relays.
Either to each of the individual accessory load circuits, or adding one to the input to the PDM from the switch just to take the load off the switch.
Powering just the computer should not put any undue stress on anything. No real need for a relay.
It’s just if you start adding other items down the road that you could consider relays.

 

[Swailsd]

Remember, though, if you start adding more switched accessories to the PDM, that put an extra load on that one wire and the switch, you should consider adding relays.
Either to each of the individual accessory load circuits, or adding one to the input to the PDM from the switch just to take the load off the switch.
Powering just the computer should not put any undue stress on anything. No real need for a relay.
It’s just if you start adding other items down the road that you could consider relays.

Only things I will be adding to the PDM would be my fuel pump and supposedly there’s a relay built in the pdm for that 25amp. And more than likely a transmission cooler but should be able to run that off the aux fuel tank wire in the harness, but not positive?????

 

[DirtDonk]

If you’re talking about a transmission cooler with an electric fan, then the fan definitely needs its own circuit and a relay.

Where do they put the relays in the PDM? I meant to ask you that earlier, because when I look at it, it doesn’t look like there are positions for relays. Unless they are under a panel?

 

[Swailsd]

If you’re talking about a transmission cooler with an electric fan, then the fan definitely needs its own circuit and a relay.

Where do they put the relays in the PDM? I meant to ask you that earlier, because when I look at it, it doesn’t look like there are positions for relays. Unless they are under a panel?

Yes under the panel built in the pdm box

 

[ntsqd]

Good grounding is crucial, particualrly when dealing with EFI but be extremely careful of creating ground loops. If any one location has more than one path to the battery's ground terminal you've got a ground loop. Those can and will cause no end of headaches. They are insidious and you can create one without even realizing that you've done it. Ground loops act like an antenna for RFI/EMI that will play hell with any signal circuits.
There are people who think this is all hogwash. It is a little difficult to believe if you're not an EE, but the first time that you deal with bad case of this will make a believer out of you. My first time dealing with a ground loop was a work situation, and we had an EE working with us! We ended up calling in a specialist consultant and he pointed out the source of the problem. We had grounded the dyno's base-plate in multiple places. As soon as all but one ground strap was removed the problem disappeared.

 

[DirtDonk]

Thanks for bringing that back up. I’m aware of them/it, but always forget about it (maybe going temporarily blind), when talking about basic grounding for Broncos.

 

[Swailsd]

Would a 4g alternator wire up pretty much like this 3g diagram?

 

[Swailsd]

Sorry about the same pic twice. Trying to figure out this site

 

[DirtDonk]

Yes, almost…
Since the 4G does not have a stator wire point, you won’t need a stator wire that might be present in a 3G/4G’s connector.
A 4G utilizes the same basic connector, but with only the outer wire positions used. Yellow wire, and Green w/red wire.
So ignore any reference to the stator wire in the instructions.

 

[Swailsd]

From the painless harness which wire should be used for the ignition switch? And I’m reading this should be fused?

 

[Jdgephar]

From the painless harness which wire should be used for the ignition switch? And I’m reading this should be fused?

In the diagram, that's not a fuse, it's a resistor.

 

[Swailsd]

It seems like I’ve read somewhere on this site that the ignition wire (maybe Painless 916 wire) would be better fused? Sorry for the confusion

 

[DirtDonk]

From the painless harness which wire should be used for the ignition switch? And I’m reading this should be fused?

When you say “for the ignition switch“ are you asking which wire should go to the 4G alternators exciter circuit?
Since the Painless harness uses the same color wire as the factory, use the existing green with red wire to go to the green with red wire on the Alternator connector.
It does not need to be fused, and you probably don’t want to fuse on it anyway.
But if you’re gonna do it right, you should have a light to indicate when the battery is not being charged. This requires a resistor bypass for safety. Otherwise, if the bulb burns out, your Alternator stops working.

This is in conjunction with a volt meter instead of an ammeter. And frankly, even without the lamp, if you watch your voltmeter enough, you should be able to tell when things aren’t working.
However, these days most people don’t watch their gauges very often. It’s a combination of younger people that didn’t get trained on it, and modern vehicles that rarely need you to monitor the gauges.
If you’re an older guy that’s used to using the gauges, you’re probably OK just to keep your eye on it.
Me personally, I watch my gauges like a hawk. But I would still like to have a battery charge indicator light.

 

[Swailsd]

Yes for the ignition switch the other wire I was talking about was fused to the starter relay. I’ve read so many threads on this site I’m getting them confused, thanks for keeping me somewhat straight if that’s possible

 

[Swailsd]

Ok guys I finally got off our annual shutdown at the plant and got back to the wiring game

I have a 3 wire bundle (alternator)
915-black/yellow alternator B+ output
914-orange alternator F
901-blk/red alternator ground
This bundle has a split with a pigtail with a yellow no number wire

Then a 4 wire bundle (Starter solenoid)
916-blk starter solenoid B+
970-brown coil+ to starter solenoid I
957-red/blue ign module start signal source
919-red/blue starter sol S to neutral safety

 

[Swailsd]

I have the 3 stud pancake style starter relay and a midi, maxi and mega fuse holders

 

[DirtDonk]

Are you asking where they should go? What kind of alternator do you have?

 

[Swailsd]

Yes, 4g explorer alt

 

[DirtDonk]

I have a 3 wire bundle (alternator)

With the 4G, some will be used, some won’t.

915-black/yellow alternator B+ output

Not used for your new alternator. However, it is a great source of power for other accessories, so you can either plan to put a small fuse panel at the end of it, or a power distribution stud.
Or you could just cap it off safely and tuck it away for now.

914-orange alternator F
901-blk/red alternator ground
This bundle has a split with a pigtail with a yellow no number wire

Black with red ground wire can still be utilized. But I would replace it with a large larger gauge wire to actually ground the alternator.
Yellow wire attaches to the yellow with white stripe wire on the new alternator connector. Verify that it has power all the time. The other end of it should either be connected to the starter relay’s battery side, or spliced into a power wire somewhere in the harness.
Orange wire is no longer used.

916-blk starter solenoid B+

Remains attached to the starter relays battery side. This is your main power to the fuse panel. Does it have a fuse already, or do they indicate you should install your 60 amp fuse in this line?

970-brown coil+ to starter solenoid I

Your new starter relay/solenoid probably does not have a “I“ post? If not, just eliminate this wire. Probably do it even with the old style, because your ignition may no longer need it.

957-red/blue ign module start signal source
919-red/blue starter sol S to neutral safety

These are the same wire essentially. We have to determine if one has power to it when the key is in the START position and the other does not. One is meant for you with an automatic transmission with an NSS, while the other is meant for a manual transmission.
Are you running a computer controlled 4R70?
I don’t remember without rereading.

You don’t mention the green wire, but I see it in pic of the bundle.
That will go to the green with red wire on the alternator connector.