paul.h

You could check if the immobiliser is recognising the key - with the key in the ignition and the engine off, open the driver's door and if it does not give a key left in message when it previously did, then the key is not being recognised. Try the spare key to see if that makes any difference. Failing this you might need to use a dealer to do a diagnostic but if you are in the RAC, etc they might do this if you call them out.

A search came up with GMcoachwork

If you think it is going to be the switch, a used one is around £30 if you do a search, a lot less than a visit to a dealer to diagnose the fault. This topic might also help https://frenchcarforum.co.uk/forum/viewtopic.php?t=70678

I have deleted your similar topic so that any replies are in one place. You could also try posting on the frenchcarforum, they have access to Citroen's procedures.

These might help http://c4owners.org/plugins/forum/forum_viewtopic.php?236597 http://c4owners.org/plugins/forum/forum_viewtopic.php?231241.0

If there is not a separate fuse then possibly the switch, its connection or the wiring may be at fault. You could check the wires where they go between the door and pillar. Do the window switches on the other doors still work ?

You could check the battery voltage, should be about 12.7 volts before the first start, below about 12.5 volts and it needs charging. For a diagnostic you really need one using Citroen's equipment to be able to check everything. When it will not start is the engine turning over, any other details, if you open the driver's door with the key still in the ignition do you get a warning showing the immobiliser is recognising the key ?

You could try posting on the frenchcarforum, they have access to Citroen's procedures so might be able to help.

Could you post this topic on the frenchcarforum, they have access to Citroen's procedures so should be able to help.

Thank you for posting this. On our C5 I had to replace a remote battery since it was not always working to lock/unlock the doors. The old battery was quite old and still had the full voltage when checked but the fault has not happened again. I also find if the spare remote is not used for a while it loses initialisation but using its buttons a lot in conjunction with the other remote it will then work without having to initialise again.

I do not have access to parts diagrams but maybe you need a new part/pipe/seal if you have a fuel leak. This will most likely need a visit to a Citroen dealer.

The fuses are listed in the handbook. If you do not have this it can be read/printed/saved (as a pdf) from the service.citroen site. You might need to select your language top right by clicking on the flag and then select your car. https://service.citroen.com/ACddb/index.html

Have you tried pushing the button on the end of the wiper stalk, on our cars this brings up the trip display for a short while and short presses changes the pages on it to trip 1 and trip 2 and instantaneous mpg/ distance left at that mpg and a long press resets it. Once it reaches about 6240 miles it stops increasing since this is the equivalent to 9999 km and to go higher would need an extra digit.

We had a C4 that was in a crash damaging the abs pump and it needed a new one. This had to be programmed with a Citroen diagnostic as well as one to bleed it.

Welcome to the forum, the car looks good now you have repaired it.

I do not know about your van but on our cars wires to the back go along the sides. Chances are if you look at where any screws are placed this would suggest where a damaged wire might be.

If it is like our older Citroens the button on the end of the wiper stalk is pressed and held in as opposed to single presses that change the trip page.

I do not know, you could ask the same question on the frenchcarforum where they have access to Citroen's procedures.

When the cabin fan stops working or only works on max speed it is often the speed control resistor pack that needs replacing. I do not know where it is but usually will be above one of the front footwells near the middle. This link might help locate it (part 4), cheaper ones appear to be available but may not be as good as Citroen parts. https://www.ebay.co.uk/itm/266232842343?chn=ps&_ul=GB&_trkparms=ispr%3D1&amdata=enc%3A1FugXaK-NSXeCcdOqzO8FgA93&norover=1&mkevt=1&mkrid=710-134428-41853-0&mkcid=2&mkscid=101&itemid=266232842343&targetid=1816181028379&device=c&mktype=pla&googleloc=9045521&poi=&campaignid=19090194174&mkgroupid=147009364227&rlsatarget=pla-1816181028379&abcId=9303860&merchantid=113098764&gad_source=1&gclid=EAIaIQobChMIv-22-_O6hAMVYpODBx2ZGwvKEAQYBiABEgIqUPD_BwE

Dan was last on here 8th Jan so you could try a message in case he does not come back for some time. Easiest way is to use the mouse over his name and then click on message and it will go by email.

Something else to check, when was the water pump last replaced. I read a topic where a car temperature was going up and it turned out the water pump impeller was loose on its shaft so was not pumping the coolant round.

I do not have the pressure values but this topic gives some measured values https://frenchcarforum.co.uk/forum/viewtopic.php?t=70186 You could ask on that forum since they have access to Citroen's procedures.

A search shows repair panels are available but if it is just a small area most people would probably make up a section to weld in place. If you have never done any welding then you may be best to get somebody who does car bodywork repairs to weld in a new section. Welding on car bodywork is often done using a MIG welder. As an example from the search https://www.burton2cvparts.com/exterior/repair-panels/repair-panel-a-and-c-pillar-2cv-50cm-long

When the air con is put on the car rpm will be increased slightly to allow for the extra load as Tricky has pointed out. Since it then runs ok this sort of suggests there is probably nothing major wrong but it might need a diagnostic to check things. If it is just when the cabin fan is put on and not the air con then that might be a different matter. First though do as suggested and check the service items such as air filter and fuel filter since if due for replacement they could have an effect. If you bought the car from a dealer you should take it back to them to be sorted. When you check the service history timing belt changes are at 10 years or 100k ish miles if sooner. Make sure you use the correct oil when changing it, it should be done every year or about 12k miles if sooner.

I do not know enough to help with this, have you tried the frenchcarforum ?