Volvo Owners Club Forum - View Single Post - V40:

nokinnikon · Mar 22nd, 2024, 18:20

I've had this problem with my 2003 1.8 S40 (B4184S2)
The headlights going out and coming back on (usually damp and cold weather) turned out it was the relays in the cem. Found a couple of them online for a few quid, desolder them to get em out then resolder new ones back in.
With regards to swapping out cem for another just make sure your one has or has not the rear wiper version, why..?
Many have purchased the S40 saloon cem for a V40 estate version only to find that the S40 saloon cem isn't set up for a rear wiper, no re-flash needed. If you are good with a soldering iron then you are good to go. There are some photos on this site someplace to guide you. Hope this is of any relevance.

Here is the tread that you need

https://www.volvoforums.org.uk/showthread.php?t=67584

Mar 22nd, 2024, 18:20	#2
nokinnikon To Roll (Latin for Volvo) Last Online: May 22nd, 2024 06:43 Join Date: Apr 2017 Location: Rhyl-North Wales	I've had this problem with my 2003 1.8 S40 (B4184S2) The headlights going out and coming back on (usually damp and cold weather) turned out it was the relays in the cem. Found a couple of them online for a few quid, desolder them to get em out then resolder new ones back in. With regards to swapping out cem for another just make sure your one has or has not the rear wiper version, why..? Many have purchased the S40 saloon cem for a V40 estate version only to find that the S40 saloon cem isn't set up for a rear wiper, no re-flash needed. If you are good with a soldering iron then you are good to go. There are some photos on this site someplace to guide you. Hope this is of any relevance. Here is the tread that you need https://www.volvoforums.org.uk/showthread.php?t=67584 Last edited by nokinnikon; Mar 22nd, 2024 at 18:30.