Cleaning lens contacts

[screech-owl]

My Canon ZOOM EF 35-75 1:3.5, used successfully on a previous Canon EOS, does not autofocus on my newer Canon 7D. I've tried cleaning the contacts with an eraser, but that hasn't solved the problem.
Suggestions?

 

[table1349]

First question, is the focus switch set to auto or is it on manual? May seem a bit simplistic but it has happened before.

 

[KmH]

Also it's much better to clean lens to camera contacts with the other end of a pencil, the lead.

 

[screech-owl]

First question, is the focus switch set to auto or is it on manual? May seem a bit simplistic but it has happened before.

I made that mistake just last week on a different lens, but not on this one. When I depress the button for focus, the green light flashes but does not remain on as it would if focus had been achieved.