Half joking about a starter solanoid isnt a joke, it would work fine. Water inj doesnt run continuous probably no more than 15 or 20 seconds at a time.

 

Thanks Loch, I think that either the pump is pulling to many amps or the 30 amp relays are way over rated. One thing I have noticed on high amp loads is that some manufacures are switching on the ground wire instead of the supply. I don't understand why but it seems to draw less of a load on the switch or relay.

 

that is actually how loch runs his systems not.. and i will probably switch it before too long.

 

????????? Please explain this, I THINK I know what yer talking about, but I'll keep quiet over here in the corner.

 

You run a fused lead directly to the load. Then you run a seperate ground through a switch. The componet must not be grounded throught it's case or it will run all the time. It's similar to the way the overdrive is wired it the automatics. there the hot lead goes to the soliniod and the ground is switched in the PCM.

 

Most ppl ground a pump for example and switch the hot wire, but it works as well if you run hot straight and switch the ground. Now i dont know for a fact if this is easier on relays but im beginning to think that it is.

 

It seems switching ground could prolong a relay's life. Whenever a circuit is closed there's an inrush of current and that causes arcing. The big magnetic contactors that were used on industrial switchgear were designed to tolerate that arc. Smaller relays have a hard time. By switching ground the current is already feeding to the motor so arcing would likely take place at motor brushes with much less arcing at newly made ground connection when relay closes.