Txwelder

I have a 12V DC pump with a hot and ground that I want to wire up with a two position switch. The switch has three legs. I am not exactly sure how to wire it up but Im thinking hot to the switch on leg one, hot from the switch to the pump on leg two and ground the switch on leg three. The two wires on the pump will be hot to the switch and ground to the frame. Is this right? Someone told me I needed a relay for my switch or I would burn it up. Is that true? Please help as I built the tank but cant use it without a functional pump. Thanks


Kevin

67HotRod

txwelder You really want a relay to power the pump. Running too high of an amperage through a switch or small gauge wire will catch your truck on fire quick. If you don't feel comfortable doing it, get some help or contact a local stereo shop for help. One wire whould be ground the other hot.

Txwelder

I dont have a problem running a relay I just dont know how to do it or what kind of relay to get.

jkitterman

Why the 2 position switch? Are you trying to get the pump to run in two directions or is that just the switch you have? What exactly are you trying to do with this pump?

67HotRod

More info would be helpful.

Not exactly what you need, but an idea. Lookup part number 555-10560 on www.jegs.com for an idea what your looking for.

HiJenks

Is this switch a lighted switch with on/off or is it on/off/on?

if it's lighted then you have the wiring idea right....put a relay between the switch output and ground at the pump. run a heavier wire, I used 10ga, from the battery/fuse block area thru a fuse to the relay and then the pump.

Txwelder

It is a lighted switch that is ON/OFF only. I am wiring this pump as a transfer pump for my aux tank.

HiJenks- Just left Yuma after six years. Sure do miss AZ.

high country

being a lighted switch there is a contact for a ground to complete the loop for the light in the switch, I would run a relay if it pulls more then 10 amps as you have a long run there, wire size needs to fit your amp draw/run length 10ga sounds like a good start.

Txwelder

Does the relay go in between the switch and the power source or between the pump and the switch? Im lost when it comes to wiring.

wannadiesel

The relay is the switch for the pump, and the lighted switch turns the relay on and off. Wire the switch to run the relay, then wire the relay to run the pump. Does that help?

The switch wiring can be very small, 18 gauge is fine because there is low current. The wiring from the power to the relay and then to the pump needs to be heavy gauge.

Txwelder

So I can use 18 ga to the switch and then 10 ga or better leaving the switch to the relay? And I can just tap my fuse box for an ingnition ON ONLY hot wire for the switch? The way it was made out to me is that I needed the relay to protect the switch not the pump. Like I said, Im a dummy with electrical issues.

wannadiesel

Not quite. With the relay you are wiring two seperate circuits, the control circuit (switch to relay) and the load circuit (battery to relay to pump).

First wire the control circuit. Go from the fuse box to the switch, then from the switch to the control side of the relay, then to a good ground. The control side is terminal 85 and 86 if you are using a Bosch style universal relay. This can all be light gauge wire. The light on the switch need a ground as well, you will have to figure out which terminal this is with an ohmmeter. It will be the one that flipping the switch does not affect.

Next wire the load circuit. Use 10 or 12 gauge wire here. You will want to come right off the battery straight into a fuse or circuit breaker, 30 amp will be fine. From the fuse go to the relay (terminal 30 on a Bosch type relay), then from the relay (terminal 87) to the pump, then from the pump to ground. This way none of the current to run the pump goes through the switch, all the switch does is turn the relay on and off.

spitfire9137

I whipped up a diagram to help you with the relay.

If you use a circut breaker make sure it is an auto reset type that way you dont have to mess with it if it trips. Also I think the terminals are numbered correctly for the relay but check the package of your relay to make sure.

Txwelder

Thanks for the visual aid. I need everything broken down shotgun style for me sometimes.