Wiring experts
 

I noticed a few days ago that the relay plugs for my fuel pumps are getting hot enough to deform the plastic. I have fuse pigtails coming off the battery that are 12 gauge wires with 20 amp fuses that go to the relay. On the 87 pin going to the pump the wire is about 4" of 12 gauge then butt connected to 10 gauge all the way to the pump. This is the pin that is deforming the most.

Also in the pic attached i have the 30 and 86 pin straight to the battery. I know the 86 pin should be on a switched 12v source but the big stuff 3 uses the ground pin 85 to control the pumps. Is there a better way to use the relays since my on/off switch is through the ground pin?

Could the relay pigtail wiring being too small? Do i need to ditch the pigtails and just run bigger wires to the relay?

Thanks

Should have put this in the tech section. Mod feel free to move.

I am no expert, but I can't see where it is wired wrong. Your box is just controlling the relays with a ground activation, and thats fine. Even 12ga wire should be good for 20 amps no longer than your car is. However impedence changes like 12ga to 10ga wire through a butt connector, will cause heat. I would soldier it together and make it all 12ga or all 10ga wire. Also check your relay sockets, the prefab ones we get here usually only have 14ga wire in the sockets, and 20amps on 14ga wire is pushing it..:bigthumb:

Aeromotive says 30amp and 10ga.

how old is the pump?

you need to see what kind of amperage it is drawing.

i didnt look at the wiring diagram because it hurt my eyes, but if it checks out check the pump.

Thanks Darryl,
I just checked the sockets and they are either 14 or 16 gauge, along with the fuse holders so im pretty sure thats one issue. Funny i bought a "30amp" fuse holder and it comes with 16 gauge wire?

I think im going to replace the fuses with circuit breakers so i can run 10 gauge wire and make my own sockets.

Is there a local place to buy the relay plugs and wire ends for them?

Paul they were actually 30 amp fuses i was mistaking.

SC-both pumps were checked out by aeromotive with in the last year but i would still like to know what kind of amperage they are pulling. I only have a Fluke 115 but im going to check the book and see if i can check amps with it.

Thanks

Wire and crimpers
 

I purchaced a Dual lug crimper which is said to be as good a solider. It crimps the lug twice, I have used it in high amp draw applications and it seems to work well if you would like to borrow it call me Mitch 843-696-7004

Circuit breakers are what the instructions call for as well.

Nothing against crimping connectors, but they are not allowed in my shop because alot of the police vehicles and such we work on have computers and such. Believe it or not you can read with a meter the impedence change in the wire by crimping that metal barrel in between the 2 wires, and impedence changes cause heat. Soldiering the wires together shows no change and will never corrode and break apart over time. Granted he is dealing with fuel pumps and not computers, but I would steer away from crimping wires espicially outside a vehicle where its exposed to weather..:bigthumb:

Chris,

I have everything in stock pretty much for 10,12,8ga stuff, if you need it. The unfortunate thing is you will have to hardwire the relay with larger wires, which is pretty easy, because the premade sockets I keep in stock, I have never found any with wires larger than 14-16ga. Give me a shout if you need help..:bigthumb:

Thanks Darryl,
I should have some of the spade connectors around the house, if i cant find what i need ill give you a call. And i do plan on soldiering the connections.

I wouldn't go that far. Ive personally seen many solder joints corrode and break over time. Solder is a more durable connection but in a car that doesn't see harsh environments (extreme cold, heat, moisture and vibration) I would never second guess a quality crimp.

I have never seen a solder joint that was done correctly break or come apart.

I normally crimp/solider.

If done correctly it shouldn't but I have seen it. If crimped correctly a connection shouldn't fail either but Ive also seen that happen. You may not have seen electronics operate in the conditions that some of the equipment that I build operates in. There could be countless reasons why you haven't seen it and I have. Usually a breakage is due to a cold solder joint but also can be cause by extremely high temps, low temps, high humidity or vibration/shock.

For maximum durability on my own stuff this is what I would do. If I was using non insulated crimp terminals.

Make sure you crimp first and solder second. If you solder first and crimp second you will break the wire. Dont forget to protect your connection point with adhesive heat shrink.

Oh I forgot to mention I agree with everything else Darryll said. Especially the part about resistance and differing wire sizes.

I do have a crimper at work that I would trust. 12 ton hydraulic crimper. Doesn't work on anything below #6 though.

Thats how the guys in the shop do the little eyelets is crimp them then fill the end with soldier, but a butt connector, never. They fail in moist floor boards in a Crown Vic, I can only imagine a military vehicle..

You hiring? I can make wires, wire harnesses, fiber optic, power, data and RF cables (both solder and crimp) like no other. I have about 12 years experience and half a dozen certificates to prove it. :razz: