Before I wire the relay up, I would appreciate clarification on three points. @77 Westy mentioned the following configuration Relay terminal connection should be: 15 Coil + (15) 30 Fuel Pump + 31 Ground- 31b Coil - (1) 87 +12V Besides the heinous crime he, by all accounts, has committed with #30 and #87 my relay has no number 31b Coil - (1) but is number 1 which I'm guessing is the same as the bracketed number Geoff used? Secondly, is the any difference between taking my 12+ volt supply from the starter solenoid (easier and closer to relay) or from the battery? Finally, if I wanted to connect a fuel solenoid cut valve that I also bought, can I connect that to this relay so that the pump and cut off get their power and start working from the same relay? Ta
Correcting my earlier serious error, it could be this: 15. Coil + (15) 30. +12v (starter solenoid) 31. Ground - Whatever is left on the relay. Coil - (1) 87. Fuel pump + (and fuel cut off solenoid)
Not from the solenoid thats only live turning over, should be a post on the main starter terminal if you're lucky where the alternator charge to the battery also passes by ... dont know why they did it that way! ..and no idea on the relay not used one like that myself Sent from my SM-T580 using Tapatalk
The terminal on the starter solenoid that also has the alternator and battery cables connected to it. – is that better? PS. And I don’t remember why I inverted 30 and 87 but it has worked for more than 10 years. PPS. I’ve just checked where I took inspiration from and know why - it has 30 and 87 inverted https://ratwell.com/mirror/www.dolphinsci.com/relay.html Never believe what you read on the internet.
I assume this is the main terminal you are describing @Deefer66? This is where I was hoping to connect to and i thought this was part of the solenoid, sorry. I understood this was permanently live and so could be used to power the relay?
Yeo the permanent live one. Tha tab above it is connected to it possibly Re 30 and 87.. it doesn't really matter by the way.. they're the two terminals that get connected when relay activated.. so can go either way as a switch DIN numbers just make it easier by having connect by numbers so 30's are usually 'live' Sent from my SM-G960F using Tapatalk
Cheers all. I must take the opportunity to clean and insulate the other connections while I doing this....not very tidy
Only reservation i have on your photo.. Red with a black stripe should be on solenoid coming from ignition/ dash Big Red white (s), from alternator and to dash fusebox and big black to battery and a smallish red to the fan at the back always live Sent from my SM-G960F using Tapatalk
Photo cropped too tightly. This was the original old photo before I took the engine out as I dont have an more recent photo, but should still be the same. The red and black is now shown. I'll check the route and colours of the others, but my main wire from the battery was and still is red, but now in a black sleeve
Relays can be marked 31b, (1) or TD for the ignition trigger wire. Hopefully you will be mounting the relay in the engine compartment, come off the battery via a fuse.
Thanks @Bigherb. I have three bits I am planning on fitting soon. 1) A hot/hard start relay - in the engine compartment, power from starter 2) A fuel pump relay - probably in the engine compartment but was wondering whether to take power from battery or starter 3) fuel cut of solenoid - obviously under camper near to fuel tank and potentially powered via the same relay as the fuel pump. What could go wrong!
Just put a small fusebox near the battery and power everything from there. Relays etc should always be mounted out of the weather and with the terminals pointing downwards.
If you really like luxury, you can buy "waterproof" relays where somebody paints a potting compound round all the cracks in the relay case and where the tags go in. Still put it in the engine bay, less weather in there.
OK, sounds like an interesting idea. I'm happy to follow a plan but my electrical knowledge is not up to developing the plan alone. So if I were to take the power from the main battery would it look something like this (the following has been edited since I first wrote this) 1) Single cable from battery terminal to Hard Start Relay (already has integral fuse) 2) Single cable to fuse box with a fuse at Y rating? connected to fuel pump relay and fuel cut of solenoid both powered together Hope this makes sense. Ta
Just fit one like this, come in four or six eight way fuses, always better to have some spare fuses for future use. You don't really need that heavier cable if you mount the fuse box next to the battery, 2.5mm2 or 4mm2 will do as the cable will only be 18" or so.
Quick check please on the wire size for the fuel pump. I have looked to see what a Carter Rotary fuel pump pulls in terms of amperage and I can't find that info anywhere. May I check what size wiring (amps) I should use # 15 Coil, # 1 Coil 8 amp wire 1mm² assumed low amp as I think these acts as signal wire # 31 Ground 8 amp wire, tiny male connector on relay so assumed low amp # 30 Fuel Pump and # 87 battery 17 amp wire 2mm² I could go to a bigger wire if needed as suggested above by @Bigherb. The male spade on the relay is 9mm (35amp?), so it suggests I use 4.5mm² wire. I may be overthinking this but I'd rather get this right and also understand rather than just follow blindly. Thanks
