S40: dipped headlight fault

[bowdi]

near side headlight fail, check bulb that's is OK.
swap with off side still near side not working,
checked voltage now this is where I getting lost when the bulb is out I got 12volts DC across the yellow and blue but when the bulb is fitted 0 volts,
does anyone have any ideas fuse OK
if i remember correctly headlight live a battery earth 12volt
and headlight earth to battery live 12 volt,
just started happening is booked in for MOT on sat

[buzzlightyear]

hi....can i ask ?? you say u checked positivly a 12volt feed with the bulb out ! im obviousley assuming via touching the terminals on the socket which plugs onto the bulb ?? then u checked 'no voltage' when plugging the bulb in ?? did u touch the bulb terminals when checking with the bulb plugged in ?? if so inspect the spade connectors on the socket which connects to the bulb !! make sure they are a tight fit on the bulb (all 3) as its fairly common that these corrode and sumtimes overheat causing the whole thing to become 'brittle' like ! if you have checked the bulb and its ok & u are also getting a live feed to the socket it can only be the spade connectors on the socket. had a similar problem with my S40 which took some sorting but eventually got there by using a pair of snipe nose pliers to tighten the connections to the bulb !
hope this helps
regards wayne

[bowdi]

hi Wayne
only 2 terminals on the back of the dipped headlight,
swapped bulbs over both fine,
can get on the back of the spade fittings with bulb in place,
when bulb in place no voltage, checking again in the same place but with the bulb removed 12 volts
regards Steve

[Clan]

this would figure if there was a point of high resistance in the circuit , is it later than 2000 ? If so look at the CEM above your right knee , see if there are wiring modifications with poor crimp connectors ... if so remove the additional wiring and solder the original wires back together , This was a mod by volvo some time ago to reduce the voltage to the headlamp bulb to increase its life , it was a piece of resistance wire that got warm and can play up at the crimp connectors .. best get rid of it !

[bowdi]

hi clan
where is the CEM located,
will have another go at it tomorrow afternoon now
cheers thanks
steve

[Clan]

hello steve , yours is post 2000 then .. The CEM is a box above your right knee , remove the dast undertray and you will see it to the right above . It has two or 3 multi-plugs with lots of wires going in ... if there has been any mods done then cut out the wire they inserted and revert to standard soldering the joints ... If all looks well there though , it may well be the CEM faulty ..

[buzzlightyear]

ah !! obviousley a later model than my 1998 ? if only 2 terminals ! didnt know about the mod volvo made to prolong the life of the bulb but im sure clan will be not far away from nailing it ?? he's pretty clever :-)
check this http://www.volvoforums.org.uk/showthread.php?t=68877
similar problems but an earlier model i think ?? i didnt read all the comments !
good luck bowdi
regards wayne

[bowdi]

Wright just finished replacing the faulty relay on the CEM unit for my near side dipped headlight that was not working, with a Matsu****a type JSM1-12-5 click on the link
http://www.rapidonline.com/productin...catref=60-4295 and switched on my lights and now its working replacement only taken 30mins from start to finish, hope this helps some of you very cheap repair