Fog lights arent working
 

Hi Volvo colleagues,

i´ve got a volvo v40 1.8 122hp from 2002 and have the problems that the front fog lights arent working. I ve checked the fuse under the hood, all are fine. Fog lights are nearly new and should work properly. I also checked the the switch in the interior and also the CEM module is already replaced with right part number.
what could be the problem ? The rear fog light is working fine.

i ´ve heard about an ECU module for the fog light and a relay. where can i find these and is the relay not included in the CEM module ? :confused_smile:

i hear no clicking noise unlike to the rear fog light and the led on the dashboard is not showing up.

greetings from germany ( hopefully thats a kind of excuse for my english :) )
thanks for your answers

Hi and welcome to the forum. From what you wrote, I guess that you replaced the CEM module. Even if the part number is the same, there are a few programmable options, such as front fog lights, rear wiper, DRLs on/off. So my guess would be that the CEM you got, does not have the front fog lights enabled. It can very easily be programmed with the Volvo DICE diagnostic tool. If you still have your old CEM by any chance, you can lug it in and see if the front fog lights are still working. If they do, then it will be 100% the CEM not having the front fog lights enabled

As a side note I was going to suggest the bulb holders themselves are in poor condition until you said the dash light doesn't appear. On mine both fogs didn't work when I bought it, one of two bulbs was blown but also both gold translucent coloured bulb holders were knackered partly due to the rubber O ring failing over time and letting water in which took care of eating away at the conductors. Strangely on Skandix the correct bulb holders are listed as not being compatible with S and V40s but they are. They are fitted to XC90s amongst other models. I replaced them and they are fine now.

Digressed slightly there but anyone else who has front fog problems may find this helps.

Thanks for the fast replies on my thread, are you sure about CEM module ? Could be any failures with the fog lights relay ? Because i think after 18 years of use and 250k km, there could be the relay that is not working right ?

I will contact my Volvo dealership, i aint got friends with Volvos at all. they all drive BMW or newer Volkswagen cars. But anyway, i´m really thankful for your suggestions.

I only mentioned the CEM because I thought you have changed it with another one. If you haven't replaced the CEM, then, it wouldn't be my first guess of why the fog lights failed.

As for the relay failing, I have never seen the fog light relay failing on its own, because it is rarely used and draws less amps than the actual headlights. 99% of the times a CEM fails, is due to the headlight relays. I have only seen 3 CEMs to-date, where the fog lights fault was because of a fault in the CEM, and it wasn't the relay, but some other issue inside the CEM board, that I couldn't repair.

When you press the front fog light switch, does the small fog light indictor light come up on the speedometer???
If yes, then check the bulbs, check the voltages on the connectors and check the earth's. If not, then it is most probably a case that the CEM does not have the front fog lights enabled

yes, i changed the CEM thats right. there is no indicator light showing up on the speedo,

I'm which case, most probably it is as I said, that the CEM hasn't got the front fog lights programmed. It's a very easy quick thing to do if you have VIDA DiCE

Do you still have your old CEM?

look at what they make you give