Hello all

Hoping you can help me wrap my mind around electric water pump control via SSR. My scenario is using a Davies Craig EWP with a Haltech 2500, using the Haltech to control it, not a Davies Craig controller. From what I understand the Hella 4 pin SSR is wired as follows, pin 30 +12v, pin 87 output, pin 86 input (ground switch/haltech dpo) 85 ground. However since the Haltech DPO sit at ground when off the pump will likely run with the car off. So if I have pin 30 be a 12 switch that should in theory work. But does my 12v switch source have to be of equal or greater amp then the pump is capable of ? Looks like about 10 amp for the pump, where could I get that 12v switch with that amp in the engine bay? It's a FD with single turbo conversion doing all new engine bay wiring currently. Thanks for your help as always.

Mike H

 

you need a DPO to control the SSR mate.

Hatlech has wiring diagrams if you need it (for a fan) and SSR
https://www.rx7club.com/haltech-forum-62/haltech-electric-water-pump-925273/page2/

 

The Hella relay won’t work for what you’re trying to do. While it is solid state, it’s designed for discrete use and won’t tolerate a frequency you’d want to use to drive the pump accurately.

Haltech offers this relay that works quite well. https://lms-efi-llc.myshopify.com/co...id-state-relat

And then there are a ton of OE pull options that work well. EVO fuel pump drivers, Corvette fan modules, etc work great as well.

 

Mike I had similar questions couple of years ago. I am running a PS1000, and normally purchase all of my electronic stuff from C. Ludwig. At the time, haltech had discontinued their solid state relay. After searching and researching for a SSR that would work, I ended up using a Dorman 902-303 Radiator Fan Relay Kit. This is a replacement SSR relay for a couple of Dodge/Chrysler vehicles. I don't have a whole lot of miles/years on the setup, can't talk about longevity, but so far it works for the Davis Craig EWP

They are back?! :O

 

Thanks Chris & KNONFS you have been a big help.
Chris, thanks for the info on the Hella relay I probably would have used it not knowing any better. I wish I had your knowledge on all the electrical systems for the FD that you seem to have just memorized. I've had my FD for 21 years or so and just the last few that I've been brave enough to tackle some of these electrical projects thanks to Chris Ludwig and the forum as well.

Mike H