I have a controller just never used it. I’ve took pressure switch all apart and cleaned it and fiddled with the adjustment screw and now it’s working right as rain 
May get the relay anyway does it just need to be wired in line with the pump then doesn’t need to be be in any certain position or anything ?
May wire in the controller at some point as putting two pumps in when I get some spare time !!
https://www.12voltplanet.co.uk/relay-guide.htmlCommon practice is to permanently mount the relay vertically with the pins downward. This ensures the innards are protected from moisture.
This is a 5 pin relay so pin 87a isn't used. Just fold that wire over and wrap some insulation tape around it.
Hopefully you have 2 wires coming from your battery to run your pump; a red positive and a black negative. Hopefully there is a 10 amp fuse fitted close to the battery on the red cable followed by an on/off switch further down the red cable. The red cable then will go from your on/off switch to the pressure switch and then into your pump. The black negative will go back from your pump to the battery. That's what you should have.
To fit the relay you need to cut the red cable somewhere after the on/off switch and before the pressure switch. That cut cable then needs to connect to pin 87 on your relay. The red wire from your pressure switch into the motor needs to be removed at the pressure switch or cut where convenient between the p/s and the motor. The cable going into the motor is connected up to pin 30 on the relay. (When this is done the pressure switch shouldn't be connected to anything.)
A new wire needs to be spliced into the red cable between your on/off switch and pin 87 of your relay. This should have an inline fuse holder with a low amp fuse such as a 3 amp one. After the fuse that wire will go to the pressure switch on the pump. The wire leaving the pressure switch that would normally go to the motor now goes to pin 85. Pin 86 on the relay will be a black wire to earth. It will probably be best to splice that into the cable from the pump that goes back to the battery.
You need to sit down and plan how and where you are going to cut and join wires. I'm a great believer in soldering joins with shrink wrap to seal and insulate it. Halfords do have a range of male and female cable joiners and a crimping tool. You will also need a roll of red and black cable as well as push on terminals. (The red cable needs to be at least 15amp, but the black cable can be of lower amperage as it doesn't carry much of a load.)
The push on terminals on the Shurflo pump are smaller than the normal 6mm connectors commonly used.
