In the simplest terms, should I be able to touch the relevant wire from towbar electrics, in this case yellow for left indicator, to the bare connection on bus left indicator on light cluster, and the indicator on trailer should work?
Yes, within reason, that'll work. Indicators can be a bit funny depending on the relay you have. Rear lights, brakes etc will work like this, no problem, although the brake lights MAY pop a fuse if it's closely rated.
Hmm. So you don't need all wiring connected up for a single lamp to work or something silly then. I'm literally touching the wire to the connector on back of light cluster and getting nothing. Tried all wires on each light. Bike rack lights are known good. Towbar/ electrics were secondhand so unknown. However I taken the socket apart, its all wired right, cable looks ok not broken/cut. Maybe try a new prewired socket?
Just thought of that and tried. ! Typical me! Got a sidelight working now. Still no luck with indicator though. How do I test that's going to work? Different relay?
not sure on the relay but if you have an earth lead and a power cable that both work then its got to be trailer at fault
Could be a dodgy wire(s) within the bunch I suppose. Think I'll just get a new prewired socket and go from there, only about a fiver. Will give me a longer cable to work with too as this ones been cut a bit short really
You either need a repeater relay or a 4/6 bulb flasher relay fitted as the extra indicators may cause strange problems. Mine seems to have an upgraded relay as all I have at the rear is a load of Scotchlock connectors tapping into the loom by the battery.
The way you're doing it is correct. Make sure the cable earth is correct. You'll need a towing relay, which will also have an output for the warning light.
As I am very lazy and Google is too big for me . Do you have a link to the relay of which you speak . . Also what warning light are you talking of . I ask cause I need to wire up a tow ball soon
You need a visible warning light on the dash or a buzzer to tell you the trailer indicators are working when it's plugged in
You'll need an indicator relay that can handle three bulbs down one side (one on the trailer) without becoming deranged. Plenty out there. I've got one made by Hella. You need some indication that the trailer flashers are working - used to be the case, not sure if it still is - something like the Hella has an additional output to drive a light or buzzer. Rather useless, but there you go. The relay should plug straight in where your stock one goes.
I took my towbar off a while back to do some work on the bus and haven't refitted it. Id didn't have doofangled relays, buzzers and warning lights. It had been on there sine Noah was a lad and worked fine! Wires were spliced and I swapped that out for a junction box to make things easier. The only problems I had were with cheap nasty trailer boards that gave in regularly!
Got a new socket, got the indicator to work, but the sidelight I had working on old socket wouldn't work on new socket Indicator working with existing relay. However Had forgotten about buzzer/flashy lamp telltale. Can't find a definitive answer as to which is needed, anyone know? Rather have a flashy lamp, those buzzers are a pita
It seems 7 pin electrics arent mot testable, so I guess as long as theres a telltale of some description, your OK ?
You may need one but its as much use as a chocolate tea pot as it doesn't tell you if its working or not, just that the point you connected the light to has a feed.
