The SKBOWE Story

In 2009 I decided that I *had* to do something about the awful halogen headlights in my 2005 S40 (T5 AWD M66). I had done HID retrofits in my other cars and never had any issues, so I ordered a kit and installed it. Everything looked great testing with the engine off, and I actually had the whole thing buttoned and was about to go for a test drive when things started going haywire. The first time I started the car, it was like a strobe light – I knew something wasn’t right and shut it down immediately and swapped back in the halogen bulbs.

Determined to continue with the retrofit but not wanting to jeopardize my baby, I took to the dear internets to find a how-to guide on an HID conversion, which lead me to the SwedeSpeed forums. But after days of searching, I never did find a guide – just a slew of inconsistent reports saying that only some kits work (usually part of a super limited group buy from a now nonexistent vendor), that after a few months you’d fry your windshield wipers, HIDs could destroy your CEM, retrofits are black magic, etc etc. It was clear that nobody really knew what was going on or what to do about it – all of the advice at the time was “what worked for me” or “it used to work, but today my WMM died” – often from the same people, only months apart, in different threads.

Intrigued, I set out determine what could be causing such a bazaar assortment of symptoms. I found the Volvo Wiring Diagrams (VWD) online, and read though every applicable section in the ViDA service program, and even dug up some additional technical literature. Curious about the “PWM” label in the VWD, and a “voltage regulation” note in VIDA, I hooked up an oscilloscope to the headlight circuit and got the first glimpse of the 82Hz PWM signal. In a long and rambling highly-technical post, I outlined what I had found and what could be done about it. In the days that followed, after some maths and a little electrical engineering, I came up with a prototype PWM filter – basically a massive capacitor bank to minimize the voltage ripple for low frequency PWM. When it worked, I set about writing up a how-to guide, and thus was born the KBOWE.

In the years since, we have learned a lot and there have been a number of HID related threads on the forums:

But they all had a sad conclusion, if you couldn’t build the KBOWE yourself, you were out of luck. Around Christmas 2016, driving through some particularly bad weather in a loaner S40, I decided that before the 10th anniversary of the KBOWE there should be a commercial product because the stock headlights are so awful. I designed a new version, called the split-KBOWE (since the capacitors that were all in one place are now split into two enclosures). After trying unsuccessfully for nearly 6 months to have this new design produced by an existing company, I decided to build some myself. Now, 8 years later, SKBOWEs have shipped around the world — testament to what an online community like SwedeSpeed can accomplish:

About Me

My name is Jacob, most know me by theshadow27 on the Volvo forums. I’m an electrical engineer living near Washington, DC (USA). I’ve been driving Volvos for 15 years; my first car (a 2001 S40 1.9T) gave it’s life to save mine – and I’ve been in the family ever since.

My 2005 T5 M66 AWD a perfect car; although it has it’s quirks (i.e. character), in the last 10 years haven’t seen anything that I’d rather drive. Besides the timeless style, rugged build quality, DIY diagnostics and surprising power, it’s really the community that makes maintaining this old gal enjoyable. The SKBOWE project is the best way I know to give back for all the support I’ve gotten from the P1 community over the years.

If you want to get in touch, drop me a PM on your favorite board:

And I’ll get back to you as soon as I can.