Old one I bet but need help asap
 

Hi
new to volvos and searched everywhere for advice on diy fitting of towbar electrics on a G reg 740 estate
can find everything about 940 nothing on 740
so far I have gathered there’s no 10 pin plug like on 940 and scotch locks are rubbish
dont think I need a relay as only running lights etc.
Its emergency tho as due to collect a caravan this Sunday
Am fitting towbar on Wednesday and planning on sorting electrics Saturday lol planning being key word
any help very welcome and as simple as possible
cheers
dave

I'm not familiar with British/UK tow connectors... in the USA there's two common kinds, 4 pin which just operates the trailer exterior lights, and 7 blade used for an RV (caravan) which needs battery charge power, electric brake control, and might have backup lights too.

US trailers have only three light circuits, left turn, right turn, and running/parking lights, the left and right turn are used together for brake lights. Volvos, like most other European cars, have separate turn and brake lights, so you need a circuit module, usually installed in the trunk, to convert them to the 4-pin (or 7 blade) trailer connectors. this circuit module usually also needs separate power so it doesn't parasite off the vehicle tail light circuits, but if your trailer lighting is all LED and you have an LED specific conversion module, you may not need this extra power.

anyways, 740 is nearly identical to 940 in most things, especially the last few years of 740, and especially the estates.