Having not worked on our 2000 S40 for quite a while, I got a chance over the holidays when my daughter returned home from school with no low beam headlights, an exhaust leak and the brakes pulling to the right. Just got the lights sorted out and here's some stuff I learned for first time DIYers:

1. Tricks to replacing headlight bulbs: pull open the flip up covers, and slide off the 3 inch round rubber weather seal to access the bulb. Yes, the low beams are the ones with no room to work. Passenger side: Remove the wire from the back of the bulb pulling straight back (or move to the side of the clip springs). Find the clip spring ends and press together to the inside to pop open, and swing out of the way (you need to move 90 degrees to make room for the bulb to slide out). Slide the bulb straight out but you may need pliers to "walk" it out if stuck. When inserting the new bulb, try to use clean hands and avoid touching the bulb glass (oils from your hand can shorten bulb live). You may find it easier to install by connecting the wire first and use that to guide in the bulb. Check to see its in square and fully seated. Reset the retaining clips. If you find one doesn't clip easily, undo the other and clip that one first (the clips can bend or shift so this helps). Driver side: Consider taking the battery out or disconnecting cables to remove the battery cover if you have one. I had zero room and would up just taking the battery out (get your radio code handy) - remove negative first, then positive. slide off cover. Remove retaining clip found at the lower left end of the battery (note the position and orientation of this clip before removing so you can recall for reinstall).

2. Oh ok, now your lights still don't work. Check fuses (maybe a good first step) The fuses for the 2000-2004 low beams are in slots 10,11 in the fuse box under the hood. Only trick here is that the fuse removal tool is in the fuse box under the dash. That's the small fuse box right under the hood latch. You don't need to remove any moulding but its really low down there. The cover pops right off and the tool is in the cover.

3. What? your lights still don't work? OK now you have two choices - the headlight dashboard switch or the CEM. Both can be had for $50-75 used on Ebay or you can pay a dealer 10x that for new. So lets replace the headlight switch first: All you need is a #2 Phillips screw driver. Find the two screws under the switch/bezel and remove. Nothing happens... the bezel is held in by the air duct and a 1/2 inch clip on top, so pull out slightly from the bottom, then pull downward about 1/2 inch, you may need to wiggle and use moderate force but after pulling downward you should see the clip you need to free - once you get to that point, you can pull the bezel/switch straight out. the switch has two press in latches on each side to remove from the bezel. There are two connectors with end latches that push to the side in opposite directions to free the wires. Assemble is reverse, just make sure you line up the small pin on the bottom when pushing back up and in.

4. Oh ok now your still without lights? Yeah it was probably the CEM all along, hopefully by now that eBay gift arrived. To access the CEM, you need to remove the kick panel under the steering wheel. There are two press clips holding the kick panel to the lower sound insulation. A flat blade can pop them apart. Now remove the four or five screws. The kick panel is fit into slots by the center console, so you will need to pull out the door side a bit then work the panel at an angle to free the tabs through the slots. You will now see the CEM unit on the left side (US not UK here) above the hood release latch. It has four connectors two of which are not easily accessed. loosen the screw holding a molding bracket next to the hood latch to make some wiggle room. Remove the screws holding in the CEM. Remove the two lower connectors by pressing in the tab in the center (I had to press the tab with one hand and pry with a small blade to walk out the connectors. Now with the two connectors off you can pull the CEM down and out to make easy access to the two remaining connectors. Open that eBay gift and connect up. (re-install goes pretty easy since you can relocate with the connectors on).

OK so that's all I did this weekend. If you still don't have lights, I'd be bummed too as your now looking at possible connector/wiring issues (time to start wiggling things) so you may want to inspect the connectors when you are removing the CEM or switch or bulbs. My deal was when the CEM went, it took out two headlight bulbs and one tail light so I suspected a module failure...) Hope these tips help those of you wondering about doing it yourself!

 

I bet you could replace those modules and sell that original CEM. Or keep it as a spare.

 

True enough. I have thought about putting the original switch and CEM back in the car as a way of testing them... Maybe I'll offer a service for testing other people's parts - just leave all those parts hanging out there for easy swap in/out... :-)