The pumps in, everything is connected...except the blue (pos) wire. I've read a few folks here have used a relay; I'd rather not do that (one less electrical component to fail).

Who here has connected to a switched circiut directly and what did you use?

Thanks, in advance...

 

A relay is plenty safe to use.. If your not extremely careful not useing a relay will set you up for failure.

I just made a trick little circut that keeps a electric waterpump running 2 minutes after you shut the car down. (prevent normal hotspotting) Even that circut relies on relays.

 

Alvin, could you shoot me a copy of your circuit? Thanks...

 

Here it is, I'm unhappy with it right now. I would like it to last 5-10 minutes.. Right now it only last 2 minutes and some change. I need help from the EE guys out there.. how can I improve this to last longer? Any higher restance than about 50k keeps the relay from coming on at all.. I guess I should look at putting anthor transistor in to take some of the load of the one i'm using now..

HELP!!!

 

Just so you know, the idea of a relay keeps higher amp drawing devices away from smaller circuits. It's a good idea to keep high amp drawing devices separate from the "key on" circuit. Good chance of over heating that circuit. I have mine set up so if the relay fails, I can bypass it with a jumper and get me home. It's been 3 years and 8k and the relay is still working fine.

 

Better, to use a relay than to have the switch/or wiring fail.

 

Right now I've got it wired to the primary fan. Mainly just to see if everything works (it did) and didn't leak (...yeah, it did). It's not going anywhere soon, the shocks are out in California being rebuilt. I probably will run a relay. Should I run the signal off the primary fan or should it go to iginition "on"?

 

You don't want to run the pump off the primary fan as it doesn't run all the time (engine running). This is especially important when you are over 35 mph when the ECU shuts off the fans. The best circuit to use as a signal for your relay is the "Key On" circuit. Here is a tech tip article that has the wiring instructions.


"Meziere didn't give us what was really needed to wire this pump up correctly. So, you need at least a 30 amp relay (Radio shack has one, but a good electric fuel pump 30 amp relay might be better as far as lasting longer). Another product that might be better is the Painless brand electric water pump relay kit from Jeg's. I just didn't know the amperage of the relay and it was $30. Also, I bought a 10-gauge wire 20 amp fuse holder with a few feet of 10-gauge wire. Some 10 - 12gauge terminal ends, Insulated female receptacles to plug into the relay, butt connectors to connect to the fuse holder and I eliminated the Mez plug connector and went with butt connectors. A better way would be to use a quality weather pack plug. Also, get some ring end terminals to connect to the "jump-start junction block." In case you don't know what a relay is for let me explain. The relay is a switch that keeps the high drawing amperage components away from areas that shouldn't have high amperage. The relay has a signal circuit that energizes the relay and makes a high amp connection. The Mez pump is a high amperage draw and we need a relay to turn it on. Where does the signal circuit get its power or signal? I chose to use the "run-on, bulb test, crank" circuit which is the one that is powered when the ignition switch is on. Where did I get the power to run the pump? From the "jump-start junction block, which is basically a direct shot from the battery. Okay, enough of electrics 101. There is a block or junction of electrical wires connecting to one source (a bolt with a nut) right behind the battery. This is 12 volt all the time power. Put a ringed end terminal on it and run the wire to the relay you bought. One of the tabs should say 12volt in. I mounted the fuse holder on top of the ASR with the bolt that holds the cover on. I also mounted the relay just under the ECM, there is a small plastic tab that sticks down and I drilled a small hole for mounting the relay. Continue the wire from the relay where it says 12volt out to the fuse holder. Connect the other end of the fuse holder to the BLUE wire of the Mez pump. I dressed it into the harness right along the edge of the fender. I used a butt connector instead of the supplied plug (too cheap). Run the black wire from the pump to a ground, I used the ground bolt just under the fan relays. Secure that wire from the pump to the fan braces via tie wraps; don't want to have it tangle with the serp belt. Now for the signal circuit. In my 92, the run-on circuit runs to the fans and it is pink with a black stripe. You can find it by tracing back from the cooling fan relays to a point where you can make a splice. If you have any pink wire at the store, you can keep the color correct for your circuit, or just use any 14 -16 gauge wire. After making the splice, run the wire to the relay and connect to the "on/off switch" tab. Run the remaining tab to ground. Again, I ran it to the same bolt under the fans for ground. Recheck your connections and that is it for the wiring. DON"T TEST IT YET UNLESS YOU HAVE REFILLED THE COOLING SYSTEM. The instructions say don't run dry. If you followed the wiring exactly, your pump will turn in the correct direction. Blue gets the power and black goes to ground. Did you reconnect the battery? Refill the oil and cooling systems. I don't use DEXCOOL; I just use the GREEN STUFF and distilled water. After you have coolant in your system turn the key on and look inside the expansion tank to see if it is flowing. Hopefully it is. This makes it easy to top off the system with the pump running. Take one more look under and through the car before you give it a test drive. Bring an extra fuse and a jumper wire in case the relay fails. You can just pull the two 12 volt wires off the relay and connect via a jumper wire with blade terminals on it. This will get you back home. Most guys carry an extra relay, just in case. Don't give Murphy a chance to strike. That's it. One thing that made this project easier was my Kwik Lift. It's a drive on ramp that you jack up. Gives you about 20 inches under the car. And it makes things safer. Hope this helps. See ya Strick "

 

We no longer leak; and I have purchased the relay, connectors, wire, etc. from Radio Shack. I'll wire it correctly over the next few evenings. Thanks Strick, for the directions on how to do it right, and the advice from the rest of you. I think I'll put a manual bipass switch next to the relay for emergencies

 

I used the same hookups as Strick. But I ordered a relay kit from ecklers that is designed for 84-87 vettes to upgrade the fan relays to the new style which is what we have for fan relays now. Anyways it comes with a mounting bracket and the plug and connectors. I think it was around $16.00. I have had it on for 1&1/2 years and no problems. This relay is pretty reliable exspecially when you compare them to aftermarket ones and since it is rated to run the fans it is plenty heavy as the fans pull more amps then the waterpump.

 

I've got a updated circut if anyone is interested in it..

Should prevent hotspotting as when you shut the car down temps typically rise quite a bit.

 

You know they're costly but you can just buy a timed relay.

 

yeah but its hard to find one that last longer than 60 seconds, they are bulky and cost almost 25 times more than building on yourself.

 

Alvin how bout this.

buy a cheap tubo timer and wire it for the water pump that way you can set a time every time you turn off the car....

would this drain the battery too much?
this is a great Idea and my hats off to you.
your friend
Sean

 

I think what I got works Ok, i've got it adjustable from 1-6 minutes pretty easy and it cost around $5 in parts.

 

Alvin I am not sure if they are available for automotive use but at work we have Ice Cube relays that have a delay off timer built in.Sounds like what you need.

 

Nope, Thanks Im fine now guys.. I revised the schematic a little and can achieve 6 minutes pretty easy. I've got anthor little mod that can give me even more time.

 

Well, if you want to be able to cool your motor down after a spirited run and it's hot, I can run my Mez pump and cooling fans with the motor off. Here is how: (sorry it's long)

https://www.corvetteforum.com/techti...=232&TopicID=2