Hi, I too had problems with my Peugeot Expert van fan, Nothing happened when I moved the slider control! My father has same van and his heater is intermittent our vans are the 1999 TD. The problem is there is little information around about these vans because Haynes have not made a manual for these vans and after emailing them, turns out they don’t plan to make one either! Doh!
I have found a manual on sale on EBay written by Peter Russek, which covers the Expert, Dispatch and Scudo. Ok so this might help you as it worked for me, Grab hold of the gear stick cover and pull it up this should separate the cover from the dash as its just a push fit design. You should have now revealed screws to take the in car charger / ash tray out. Take it out and this will reveal the screws to take the cover off of the sliding control unit for the heater. First pull all four knobs off of the sliding controls as they are a click on fitting, and then unscrew the cover from control unit. This will reveal a rectangle shaped control box, with a cable and wires coming out the sides. Here you need to unscrew the cover from the unit and pull this out, this is a little tricky but don’t hold back the cover has 3 small light bulbs on it good time to change any that don’t work, the cover has contact points on the back that are probably dirty like mine was so give it a good rub down and clean. Also clean the copper contacts that are on the base of each slider control and make sure they are bent up to make a good contact with the back of the cover. Once you have done this place the cover back on and do up the screws you can now turn the engine on and try the control unit before you put the rest of the covers back. If it now works great if not re check the copper contacts for good contact on the back of the cover.
Also you need to check the fan its self. I found that although the power supply to the fan was plugged in to the unit the contacts were tarnished within the plug and the plug was a loose fit, I cleaned them off and connected the plug back into the unit. The Fan is located just above the passenger foot well and you can see it by getting down on your hands and knees and looking up behind the dash. You will see the power cable going into the bottom of the unit so just pull on it to separate it and take a look at the plug, clean the contacts (make sure key is out of ignition) and give it a firm push back in. Good luck.
James Lucas, December 2007