Wiring for Dummies -101 ... Need advice

[6600DURAMAX]

I do not know what else to call this post other than that.....

I need some advice / guidance on how to understand wiring

Trying to understand relays - how they paly a part - is the fuse panel sufficient enough or is their another in-line fuse needed in situations ??

What I have
1- New Painless complete wire harness
2- PSI LS3/6L80e Wire Harness
3-Duel Electric Fan setup
4-Aermotive Stealth 340 In tank Fuel Pump

Lets just start with Fuel pump - I thought that would be easy enough but I'm confused - both the Painless and PSI harness have wires for fuel pump. Do I run the hot wire from the fuel pump to the Painless harness ? Is that my "fused" connection -- then I run the PSI Fuel pump wire to the same terminal on the Painless harness?

Fan - same situation - have a spot on the Painless harness for fans but then the PSI Harness Diagram also has two separate wires for fan control. Then when I look up the Spal wiring diagram it shows fuses and relays - how do i separate what is needed and what is not ?

[6600DURAMAX]

Some additional pics of this wiring nightmare - you can see the smaller PSI fuse panel and the larger Painless fuse block in these pics

[6600DURAMAX]

fan diagram from PSI paperwork and then from Spal website '

[CarlsLQ9SS]

I would control the fuel pump and the fans from the psi engine harness. The computer will know when to command them on or off. And I would remove the fan and fuel pump wiring from the painless chassis harness to clean it up.

[CarlsLQ9SS]

And your fuel pump and fans will both need to be run through relays because of the amp draw each one requires to operate. The psi harness should already have a relay for the fuel pump but in my experience you will need relays for your fans, one relay for each, one high and one low speed fan if you have 2.

[dmjlambert]

There is a good discussion going on now in this other thread Electric fuel pumps are dangerous. If I were installing an electric fuel pump I would include both oil pressure and inertia cutoff switches for the fuel pump. I wonder if the wiring for relays and cut off switches are included by painless.

[6600DURAMAX]

Originally Posted by CarlsLQ9SS

I would control the fuel pump and the fans from the psi engine harness. The computer will know when to command them on or off. And I would remove the fan and fuel pump wiring from the painless chassis harness to clean it up.

So I'm interpreting from your above statement that I do not need to try to "tie" the harnesses together - Just use the PSI harness for fuel pump and fans - that makes sense to some degree.....

[CarlsLQ9SS]

Originally Posted by 6600DURAMAX

So I'm interpreting from your above statement that I do not need to try to "tie" the harnesses together - Just use the PSI harness for fuel pump and fans - that makes sense to some degree.....

Yes, I don't think you would need both harnesses to control the fans and the fuel pump.

[LS short box]

I've used Painless harnesses on a few LS swaps with very good results. The ECM will need a 12 volt signal constant and 12 volt signal in start and run and that will come from the Painless harness. The fuel pump will be controlled by the ECM thru a relay that is supplied (hopefully) by the PSI harness.
Does the PSI fuse block have two relays or three built in? From the pic of the PSI wiring diagram it's supplying the fan relays and the two wires that go directly to the fans 1 and 2. It's nice to have the fans controlled by the ECM because then in the tune you can adjust temps and turn on as needed with your Vintage air setup.
I haven't used AC on a LS swap but as I understand that most running AC turn on one fan as soon as the AC comes on just like a late model car.
Per the pic of the Spal setup it looks like it's turning on both fans at the same time controlled by the single temp sensor. The down side to that is it's going to pull some serious amps when both fans come on at the same time.
My 98 Wrangler LS6/4L60E swap is wired that way with the sensor in the radiator tank but with only one 16" fan. Has worked fine for almost 15 years. On at 205 and off at 195.
The Painless and PS1 are really both stand alone. Painless for the chassis and PSI for the engine control.
I haven't used PSI but they have a good rep over on LS1tech.com. I've used Speartech and Howell on over 10 LS swaps, mine and my car buddies projects.
I would contact both PSI and Painless with questions. I've been to the Painless plant in Fort Worth and met the owners. Super nice guys and I've found their tech guys to be really helpful. I have not used PSI.
Do not skimp on good grounds. Battery to engine block. Engine block to frame. ECM grounds to the engine block.
Good luck and by the way I really hate wiring. LOL.

[Accelo]

I have SPL fans and mine came with two relays.
They can be purchased inexpensively.
Below is a link to relays rated for the amperage of your fans:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
The link is for three relays and you only need two. I like the way they interlocked. Helps keep it neat.

No need to use the external temp sensor or the manual switch.
You may not need the relays? I suspect one of the relays built into the harness is for the fuel pump and the other two for the fans? You will have to check instructions for the relay applications.

Painless harness requires a decent crimper. They sell them or maybe even rent them? The standard crimpers will not work. I also recommend a de-pining tool set as they are difficult to get out if you make a mistake. When you pull on the wire while attempting to de-pin often you will pull the wire out if it isn't soldered. I recommend soldering for your first wiring attempt.

Hiding the wires, so everything looked clean, took way longer than anything else. I used a old 12V drill battery to test each circuit, when I was finished. The air-conditioner takes up a lot of room and I suggest you have it installed loosely for the wiring installation. You will likely pull it out and in several times during the process.

Do not forget to install the dash pad first! It's a PITA after the dash wiring is in.

[6600DURAMAX]

Great suggestions guys - especicllly on the dash pad portion ....

My plan is to call PSI today

It will be next weekend before I'm able ot dive back in to this but it will give me time to order the relays and fuses

Anyone have suggestion or pictures of their "power distribution" block thee used ? Seems it would be nice to have a small one to feed the constant power to multiple items like the ECM, ampilifer, ect....

[LS short box]

I took another look at the PS1 document. It says the two fan wires go to the negative side of the relays supplied by you.
One thing I didn't like about the Painless kit was mine (s) were supplied with those cheap blue butt and spade connectors. Pretty much thru them away and went to Fastenal and got the connectors that have heat shrink tubing and some type of goo on the inside that melts when you shrink the connector giving you a water proof connection.

[MARKDTN]

Do yourself a favor and buy good relays. Good relays can be had made by Hella, Bosch, and Tyco. Even some of them are China made so beware. I like to make up my own sockets so that there are no splices. Good kits with relay sockets and terminals are available. The fuel pump won't pull high amps so a normal 30A (good quality) cube relay will be fine. For fans you need to be careful. Most electric fans pull more, especially at startup. I like at least a 60A one like a Hella 003437-08. The socket (and terminals) is different than the more common ones so be aware of that.

[LS short box]

As said above buy good relays and keep an extra in the glove box. Over the years I've only hade one go bad on the way to the big car show in St.Paul MN. The Painless guys were there and they gave me a new one no charge!
I also keep an assortment of blade style fuses in the glove box just in case. Never had one go bad or blown.

[6600DURAMAX]

Will be contacting PSI and using their fan relay kit

I also need some guidance from them on the 3 relays in their wiring kit .....