Having done most of the other jobs, suspension / brakes etc turned to the high idle when warm (1200).
Checked for leaks with brake cleaner spray none found.
I suspected the ISV cigar tube which didn't seem to buzz much but cleaned and you can see it energising as the relay(s) in the black box clicks. Tried a spare that behaves the same.
One of the two wires (white) was bare under the rubber cover so replaced the socket properly.
Next suspected the tail light black box. An electrically knowledgeable friend replaced the power transistor which looked a bit burnt and checked through as many components as possible all now seemingly within spec.
New improved ISCU control box refitted but now idles at 3000+ rpm rising towards 4000!!!!!
There must be a more fundamental problem. Wiring short in the loom??? Will check temp2 next. Any other
ideas help
![Embarassed :oops:](./images/smilies/icon_redface.gif)