Are all 406 Coupe V6's (194bhp engine) fitted with aircon? And if not did these cars have a shorter auxiliary belt or did they use the same belt and just relocate/install pulleys to take up the resultant slack?
Yes, they all have air conditioning. So there is only one type of belt, Peugeot part no. 5750S9.
The saloon and estate models could have no aircon with that engine, and these had a shorter belt, part no. 5750Q3.
I doubt that the shorter belt would fit the A/C engine. AFAIR there is a substantial difference in length.
What I meant is that the longer belt is for A/C engines (coupe, saloon, estate),
and the shorter belt is for engines without air conditioning (saloon and estate only).