I bought my first Volvo (S40 1.8i 1998) three months ago. Despite of all the stories I heard about GDI motorors, it works fine and I really enjoy driving it. But there is a very strange constellation of electrical problems I can not understand. All my interior lights do not work, neither reversing lights. All fuses seem to be perfect and bulbs are fine, too. I have already tried to change fuses and bulbs, but the problem is still the same. I have the feeling that these two problems might be two different problems, but I am not sure. Does anyone have any ideas what could be cause this? I would appreciate any help. Thanx.

check the relays

Thank you for your answer. Could you tell me where I could find the relays for interior lights? Where can I find a wiring diagram showing the position of relays? In the manual of my car only the fuses are shown. Thanx

the relays are under the drivers side panel. near fusebox

first if you can, get a circuit tester and see if its a open circuit (life going tho the system (i.e find good earth and test the reversing lights and interior light connectors))

also if relay is working you should hear a click if it is working when you engage the the item. if not its normally the wiring or component that is at fault.

the reserving light switch is actually located on the top of the transmission unclip it and unscrew the bit left in the transmission and check that, that could be your reversing light problem. if the relay is good and all else fails that is :57:

Thank you for your answer. I took of the cover under the dashboard and saw two relays inserted in a white board. One of them, the left one was hot, the other cold. They were the same, so I changed them. After a while again the left one became hot. Could it be the problem? If so, it should be with the board, not the relay. I saw that next to the fusebox there is the relay for turning sign, and also could touch some other relays, but could not really reach them. Do you know by chance which is the relay for the interior lights? Cheers & thanx

correct me if i am wrong, but a hot relay should mean there is resistance somewhere. are the panels where the bulbs are okay? have you looked to see if there is anything wrong with the bulb holders?