SwedeSpeed P1 (C30, S40, V50, C70) HID Retrofit Index
- SKBOWE Plug-and-Play harness for P1 HID conversion
- Background info, general questions, and share your HID setup
- KBOWE How-To (Original 2009 Version) build your own PWM filter (you are here)
- Original 2009 investigation and technical discussion on S40 HID issues
- ForceFed’s E46 D2S Bi-Xenon Projector Retrofit guide
- Rewire OEM Bi-Xenon headlights to work on the halogen harness
- DRL Disable Alone not enough for safe Aftermarket HID retrofits
- LizardOfBodom's EU/RHD Bosch ("E46") Bi-Xenon replica retrofitting writeup + angle eyes + running lights
This thread is the official "How To" writeup of the KBOWE, a DIY PWM filter for P1 cars - please only post here for support in building, installing and testing an KBOWE.
As of June 2017, if you don't want to build this yourself there is finally an assembled version of the KBOWE called the SKBOWE. See skbowe.com for a plug-and-play version of this PWM filter for HID retrofits in P1 cars.
If you'd like to share your experiences on an aftermarket HID installation working (or failing!) in a P1 car, that is S40/V50/C30/C70N, with or without this sort of box, please post in the statistics thread. Thanks!
NOTE: If you've got an S60, it might not be possible to disable the PWM modulation on the low beams. The KBOWE described below should (additional information would be appreciated) allow a successful retrofit (although the install instructions will be different), however there may be an easier way with a relay harness and the parking lights.
"Told Ya So" disclaimer:
WARNING: Do not attempt to operate an aftermarket HID kit in a P1 S40 / V50 / C30 / C70 before reading and understanding the issue described below. While a kit may turn on, the PWM DRL regulation will drastically shorten the life of the HIDs, and can potentially damage the (Windshield) Wiper Motor Module (WMM) and/or the Central Electronic Module (CEM), both of which are several hundred dollars to replace.
Newer Volvos, specifically the P1 chassies (S40N, V50, C30, C70N), with halogen (incandescent) headlamps use the low-beam projector for the Daytime Running Lights (DRLs). Because the bulb is on whenever the car is running, Volvo engineers decided to add a form of voltage regulation called Pulse Width Modulation (PWM) which extends the life of the halogen bulb. This form of regulation prevents aftermarket HID ballasts from operating correctly. he KBOWE described below is one method to allow an aftermarket HID system to be safely under such conditions. It works by filtering the PWM voltage, turning the pulses into clean DC voltage.
The device described below only partially addresses the problems with HID retrofits in P1 cars. PLEASE read this overview completely before you proceed!
KBOWE Write Up
This write up covers the construction of what DDM calls a "BOW Eliminator", or what I call a PWM filter. Its purpose is to let aftermarket HIDs run on factory wiring on Volvos (or any car) with PWM voltage regulation on the low beams. The S40N/V50/C30 have this "feature", as do some other newer Volvos. so this thread is just how to build it.
- Soldering iron + solder
- Wire nips
- X-Acto knife
- Step bit (for grommet)
- Dremel abrasive disk (or cutoff wheel)
2x 22,000uF (22mF) 25V capacitors minimum. Recommended: 33,000uF (33mF) or 47,000uF (47mF) 35V, rated for at least 2000 hrs at -40c - 105c. e.g. ECE-T1VA333FA
2x 10A 50V TO-220A Schottky rectifiers minimum. 40A 200V recommended for safety margin. Ultra low forward voltage drop is key, MBR1045PBF-ND
1x Prototyping board, perforated.
1x Plastic project enclosure large enough to hold the capacitors. You can use any enclosure you want, or none at all (just pot with silicone and wrap with electrical tape).
1x 1/2" Rubber grommet
4x Male bullet connectors (or Quick Disconnects)
4x Female bullet connectors (or Quick disconnects)
~2m 14 or 16 gauge stranded automotive wire, various colors and black
1x Tube of RTV silicone
The capacitor specification is a minimum, the bigger the better up to around 50mF. Capacitors in parallel add - so you can get less expensive smaller capacitors and wire them together:
The enclosure doesn't matter as long as it can hold everything.
Parts Cost - If you order enough to make just one and have nothing lying around the shop to use.
2x Diodes @ $0.31
2x Caps @ $2.36
1x PCB perf board @ $1.99
1x Enclosure @ $2.69
1x Grommet pack @ $1.99
1x Pack bullet connectors @ $1.95
1x Tube RTV silicone @ $5.97
6' 14AWG stranded 4 conductor @ $0.90/ft
Total = 25.33. If there's no radioshack near you order everything from mouser/ebay. Shipping will probably be more than parts, so I'd buy extras.
Modding the case
If you decide to use 4x2x1 radioshack enclosure, you'll find it's too short to fit the 30mm caps. I used two 7/8" sockets and a heat gun to indent the lid so the cap:
Move the heat gun quickly over the case until it softens up. Then apply an even pressure to smoothly bring out the bumps. You may have to try this a couple times before it works out right - just keep test fitting the caps until they just slightly have wiggle room. Silicone will fill in the gaps later, so it should not be a press fit.
Next, you'll need a 1/2" hole for the grommet:
It's easiest to put it in before everything else.
The schematic for the circuit is:
In real life, these parts look like this:
Building the diode board
Install the diodes, bending the leads down so the TO-220 case lies flat with the board.
Insert wires into the PCB with the diodes. You should use two different colored wires here, I used red for "in" and orange for "out". Make sure the right color is going to the right terminal on the diode (see circuit overview). If you mount them like below one will be backwards (see blue dot in pic for the anode) so be careful.
Here's how we're gonna wire it:
Flip over the board and solder the wires to the diode leads. Make sure to get nice hot joints, cold solder joints break fast in a car.
Not shown here is two additional wires that come off and go to the caps. They are connected to the red pads on the reverse side. You'll see them later on.
Wire the capacitors
For the negative terminals on the capacitors I used a single black wire, stripped the end, and sliced the insulation further down. This lets you push the insulation towards the stripped end and makes two nice places to solder. If it's easier you can do it with two wires.
Here's the two extra red wires. They go from the back of the board (this was just to save space) on each red pad to a capacitor.
I nipped, stripped, and soldered them in place to make sure the wires weren't too long. Also everything was threaded through the grommet.
It's easiest to see in the next photo, there's a small white piece of plastic between the PBC and the caps. I put that in there thinking it would stop the caps from rolling into the PCB, but looking at it now it's unnecessary since the whole thing is gooped anyhow.
Everything assembled at tucked in:
You might have to use a Dremel tool to take off the smaller plastic standoffs in the bottom of the case to get everything to lie flat.
At this point (with everything how it will live when the top goes on) it's a good time to do some tests.
Physical testing: Wiggle all the wires by hand and make sure nothing breaks off. Yank hard on each wire in the bundle and it should remain intact.
Electrical testing: Unless you have a bench-mounted HID work light (like me ) the first test will have to be in the car. There are a couple of options for this, I tested it after I cut the wires at the CEM (see the appendix), using an alligator clip to ground at the cigarette lighter. It's also possible to test in the engine bay, assuming you have a long enough ground lead to make it to the frame. Best to try one side (of the circuit) at a time.
It will be pretty obvious if you've hooked something up wrong, either the HID won't light or a capacitor will explode. If the HID doesn't light up, the most likely cause is either the diode hooked up backwards, or you have switched the input and output when installing it in the car (see troubleshooting).
If all goes well, disconnect everything and fill the case past the rim with clear RTV silicone (the colors have other stuff in them). Make sure some gets under the capacitors and there are minimal air bubbles and gaps. This is half full:
Once it's topped off (everything completely covered) screw on the top and wipe the excess silicone from around the joint. As long as you're not too hard on the wires you can install it right away. To be extra safe you can wait a day or two, but it will cure just as slowly in the car as out.
Steps for install are:
0) Unlock all doors, remove the key, open the driver's door, and wait for the interior lights to turn off.
1) Remove two clips and cloth kick panel cover from under glove box.
2) Unscrew the two thumbscrews securing the CEM (fuse box) to the chassis.
3) Swing down the CEM (fues box) - it is on hinges.
4) Unplug the right most connector (green) on the fuse access side by unlatching the retaining clip and swinging it about 100 degrees.
5) Determine the two correct wires to tap. Consult Appendix A for additional information.
6) Cut both wires about 3" from the connector, and strip off some insulation.
7) Crimp female bullet connectors onto the wires on the connector side of the cut.
8) Crimp male bullet connectors onto the wires on the harness side of the cut.
9) Plug the BOWE input wires (that go to diodes) into the female bullets on the connector side.
10) Plug the BOWE output wires (that go to the capacitors) into the male bullets on the harness side.
11) Zip-tie the BOWE wires to the factory harness.
12) Re-insert the green connector into the CEM and latch it in place.
13) Swing the CEM back into position
14) Secure the CEM using it's two thumb-screws
15) Remove the small plastic nut securing the carpet to the wall (near the door jam) on the passenger side.
16) Remove the door still by pulling straight up.
17) Fold the interior carpet away from the door.
18) Follow two black wires that run along the body down to a ground stud
19) Bolt the black wire to one of the ground studs
20) Shove the BOWE somewhere under the dash
21) Fold the carpet back, secure it with plastic screw thing
22) Snap the door still back in
23) Re-clip the cloth kick-panel cover under the CEM.
* disclaimer - this is from memory. If it's not exactly right, use your imagination.
There is a relatively simple test procedure with a DMM (volt meter) and a 9V battery (or car battery) to determine if a KBOWE is working correctly. There are five wires that come out of the box: two input, two output, and one ground (call GND). Call the battery terminals B+ and B-.
(1) Connect GND to B-
(2) Connect all other wires to B+ for 10-15 seconds
(3) Disconnect battery without letting GND touch any of the other wires
(4) Measure voltage between GND and each other wire (using DMM, connect DMM- to GND and DMM+ to one wire at a time)
(5) Using masking tape or something similar, label the voltage measured on each wire
Interpreting test results ("low" = voltage reading close to zero, "high" = voltage reading close to battery voltage, e.g. 9V or 12V):
* If all four wires read low [DEFECT CONDITION]:
(a) You used the wrong lead as GND -> Repeat test with correct ground wire
(b) Problem with connections inside of KBOWE -> Correct connections inside of KBOWE
(b) Problem with capacitor wiring inside KBOWE -> Replace capacitors and check circuit connections
* If all four wires read high [DEFECT CONDITION]:
(a) Diode anode is hooked to capacitor positive terminal (circuit constructed incorrectly) -> Correct circuit connections
(b) Diodes are defective -> replace diodes
* If three wires are low and one is high, or three wires are high and one is low [DEFECT CONDITION]:
(a) One of the channels has a problem. Same corrections as above.
* If two wires are high, and two wires are low [TARGET CONDITION]:
-- The two wires that are high are the outputs
-- The two wires that are low are the inputs
-- The circuit is functioning correctly
If you know for sure that you have the input wires connected to the CEM, and the output wires connected to the wiring harness, then the only option is to remove the BOWE and correct the problem.
You can't just switch the red and orange leads, the capacitor must be on the cathode side of the diode (closest to the HID). And if it is already potted, unfortunately you will have to build another KBOWE, since there is no good way to un-pot a circuit like this. Test the next one before potting!
----------- Will be updated as info comes in -----------
Appendix A: 2004.5 -2007 Volvo S40/V50 CEM wires:
Pin 25 green-violet (passenger)
Pin 37 green-white (driver)
The connections to the circuit are:
------------ Working installs -----------------------------
- My original prototype of this project is still working (9-17-2009 - 2005 S40)
- Kyle finally got this installed (11-11-2009 - 2006 S40)
- Built one for Cliff after one of his Sharp HID BOWE's failed (12-21-2009 - 2005 S40)
- Mika built one and got it working with 35w HIDs (1-17-2010 - 2005 V50)
- vinopa30 got one working with 55w DDM slim ballasts in a 2008 C30 (2-26-2010)
- After a long battle, we got heico2.4i's 35w Raptors working with a KBOWE V3 in a 2006 S40(3-26-2010)
- Ben got his KBOWE V3 hooked up with 35W DDMs in a 2005 S40 (1-24-2011)