Hi,

my 99 D 5.9l here in Riyadh developed a random occurring idle speed issue. One set of red traffic lights perfect, drive to the next set and it's 1200 rpm plus. Dealer replaced IAC - no joy. I suggested to him that posts in this forum mentioned cleaning top most connector on back of the alternator.

This was met with a certain amount of knowing contempt...

So when faced with the engine revving controllably at 2,500 rpm at the Bahrain border I decided to do the job myself. Examination of the snap connector indicated that the plastic had degraded and become brittle with age and heat - so I went to a scrap yard and snipped out an identical connector off a wrecked D. Installed it on my D and voila, problem solved....

Question is, why does connection to the alternator so effect the idling speed...??

Chris