Good evening all, my first post and I'm really happy to have found this site. I have a Primus caravan/trailer brake controller which is showing the letters S.T on its display when the van (which has a 7 pin round plug), is hooked on. Clearly this is a wiring issue but I wondered if anyone either a) can recall this subject being previously discussed or b) perhaps can offer a solution (I am absolutely useless at anything electrical!!). Many thanks in advance.
Can't help you with the ST display. The chart shown above is for a Tekonsha Prodigy brake controller and may not be much help. If you are not electrically minded then I suggest you see an auto electrician and get the problem fixed properly, and safely.
EJP