Gramps

iTrader: (1)

for all you guys who have electric water pumps, i was wondering how you wired it, obivously i can wire it simply to the battery and have a simple toggle switch which i can activate remotely regardless of engine status. but im looking for something more forgetfull friendly. i wanna hook it up like my fan is, i bypassed the relay and now it comes on when my ignition is in the ON position and turns off when i take the key out. id like to have to same situation for my water pump but was wondering if i can draw off the wire for the fan, its a 15amp circuit and the pump is designed for a 15amp circuit. so my question is...can i run the water pump off the same wire as the fan and not manage to blow the 15amp circuit?

thank you
Gramps

ringo234

Now don't take what I'm going to say as Gospel, but why not just buy another relay (same as for the fan) wire to input side to the ground and any wire that gets hot when you turn the ignition switch and the output side to the water pump?

I think that should work. Maybe throw in a fuse on both sides to be safe.

MrDude_1

the fan only comes on when the car is running over a set high temp.

you want the water pump to only be on when the engine is running.



the simplest way to do this is to run it off of the fuel pump relay wire...

run a new, fused power wire for the electric waterpump... ground one relay coil wire, and splice the other relay coil wire to the fuel pump relay turn on.

this will make the pump turn on for 5seconds when the key comes on.. and then only run when the engine is running.. just like the fuel pump.




for a switch that changes between auto and on, do the same except on the relay turn on coil:

take a 2 position, 3 pole switch.

connect the middle tab of the switch to the relay turn on.
connect one end tab to the fuel pump turn on.
connect the remaining tab to +12v... you may put a light in series before this wire, if you want a "pump on" warning light (so you dont kill your battery)




doing this causes the switch to:

in position 1... it connects the relay to the turn on for the fuel pump... so its automatic.

in position 2... it connects the relay to power.. so its always on.


there is no "i forgot to turn it on" position unless you buy a 3 position switch ( on-off-on instead of on-on )

84z28350

^^^

Good idea


I would just wire it in with a relay, have the relay switched by any thing that is hot with ignition on. Turn the key, the pump comes on. I would personally not want all the extra wiring runing around the car for a toggle switch! its got enough wires running through it

Gramps

iTrader: (1)

altho a good idea in theory, if i wanted the pump to run when the engine was running then i woulda done nothing and therfore not posted. but since i am posting it can only be assumed that i want to run the pump when the ignition is on reglardless of the engine running or not.

the reason is because after makin runs at the track you notice your engine temp a little high, well to make it go down all i have to do is turn the ignition on. it goes down in minutes.

ive already decided that im going to run it off the fan relay since it only draws about 8amps, and btw the relay only delivers power to the fan, there is always 12V going to it, ill just tap into that wire (its big and white).

and becides...i dont even think the fuel pump fuse is 15amps.

MrDude_1

i think you missed the entire point then.

yup. you missed it entirely.
go re-read.

Gramps

iTrader: (1)

aha i got it now...thank you...ill deff try to do that.

Gramps

iTrader: (1)

so i was lying in bed last night trying to understand the wiring, but am totally lost. i need a diagram because its too complicated for a guy like me.

MrDude_1

its not too complicated.. .heres a pic and a circuit

Gramps

iTrader: (1)

what is the purpose of the relay?

MrDude_1

the electric waterpump pulls a large amount of current.

Gramps

iTrader: (1)

so the relay does what?...and how do i go about getting one of these relays? can i just go to a parts store and ask for relays?, if so...what do i ask for?

MrDude_1

yes, you can grab almost any off the shelf automotive relay.
if you go into a autoparts store, you can tell them you need a relay for an aftermarket accessory.

if the guy looks like this --> then just ask for the manager.
they do have them there. hopefully you wont get an idiot parts guy.

or you can look near the electrical or aftermarket lighting area.

all you're looking for is a 12volt automotive relay... either get one with a connector, or get one that you can use crimp connects on.
----------
oh, and heres a basic explination of how relays work:

http://electronics.howstuffworks.com/relay1.htm

Gramps

iTrader: (1)

ok dude...now final question, because im already very gratefull for your help, where is the fuel pump relay and which wire should i be tieing into?

Gramps

iTrader: (1)

now if i put the switch to position 2 (always on) then the fuel pump gets no power and the car wont start...

do i have a correct assumption?

MrDude_1

no.
you do not cut the fuel pump turn on wire.. you tap into it.

imagine the wire coming from the ECM... it forks into two wires.

one fork goes to the stock fuel pump relay.

the other fork goes to the switch






because one goes to the stock fuel pump relay still.. it still turns on that fuel pump relay, regardless of switch position.



when in the "always on" position, the other "fork" is basicly connected to nothing.... and has no effect. its like it isnt even there.

Gramps

iTrader: (1)

Gramps

iTrader: (1)

so where is the fuel pump relay? i tried to search on here and on google but no luck on its location. can you mayb give me an idea as to where to look under the hood?

MrDude_1

on the firewall, drivers side, there are at least two relays in this little "box" holder thing.

one is a fan relay. (or two, if its a dual fan car)
one is the fuel pump relay
one may be a MAF relay, if equipped....


this is a picture i found on my computer.
i can not be 100% certain it exactly matches your car. but its probably close.

as for the wiring, i only have the schematics for 91 camaros, and the wire colors may have changed... you can and should double check me with a multimeter.... set it to 20V scale, ground one probe, and test the wire by removing the relay and putting the other probe in there.... when you turn the key on, you should measure battery power for about 5 seconds, then it shuts off...

now in the wiring i do have and know, the wire you want is dark green with a white stripe....

Gramps

iTrader: (1)

awesome...