500 sel idle speed control unit location

[paulpic]

Hi all.
I have a 1983/1984 500 sel which was imported in Australia and have high idle issues which i believe is a common thing.I have tried changing idle speed control valve,fuel pump relay and over voltage regulator but still no good ,next is will be idle speed control unit (electronic box) but it is not situated in the fuse box according to manuals i have .Can somebody tell me where its located.
contact me on
paulpic1@exemail.com.au