towing wire,3 wires came out while fitting

rr

The loose thick one is either the relay supply from the battery or the supply to the component (check both thick red wires with a tester to see which one is supplying power).

In normal set up,the power is Pin 30 on your relay

The other is ground Pin 86 and switched supply Pin 85

Power out from the relay is Pin 87 (both these are red on yours, ergo one is feed in the other out)

So,loose red may be the supply from battery

The other red may be to the component needing a large draw

The green may be fro the switch

The white may be earth

You will need a tester to check

Does that make sense?

fd

Found this...may help

https://4.bp.blogspot.com/-t40XfOSx...-4s33SKuH8aoJZH_rpzuQCLcB/s1600/EureTech6.jpg