P1 HID Retrofit Guide

This page will walk you through a WMM-safe and error-free HID retrofit process for your S40, V50, C30, or C70 P1 Volvo vehicle, avoiding the serious issues that incorrect component selection or installation can cause.

You have 3 choices to make before ordering components:

There are also some sample configurations and ballast recommendations.


You have some decisions to make regarding the approach to your retrofit based on time/effort, budget, and goals. These are entirely personal – I’ve tried to outline the various options with pros/cons based on these criteria, hopefully you find it helpful. Wherever possible, I’ve included links to relevant info on this and other sites.

My typical recommendation is to go with SKBOWE + 50W + Rebase bulb at first – and look into a projector swap if you aren’t happy with the cutoff. But the decision is yours – and the following sections should help you decide how to power your HID retrofit, which optics package you’ll go with, and what ballast brand and wattage to choose.

Decision #1 – Power: SBKOWE or Relay Harness

There are two safe ways to power an HID retrofit in P1 cars – either using a SKBOWE or a Relay Harness. The relay harness is cheaper at the base configuration, but if you don’t want the “BULB FAILURE” message, it’s only another $20 to keep all of the stock functionality, fuses, and messages with the SKBOWE.

Why mention the relay harness on an site dedicated to the SKBOWE? Because it will work and I hate misinformation and deceptive advertising. I believe the SKBOWE is the best approach, and don’t mind explaining why.


SKBOWE system diagram
SKBOWE system diagram

Relay Harness

Relay Harness System Diagram with load resistors and anti-buzz capacitor



A pair of SKBOWE you can get from the order page of this site.
Relay Harness

Morimoto anti-flicker relay harness and load resistor from TRS
DesignDesigned for P1 Volvos, easy install directly behind headlight, correct amount of wire, invisible with headlights installed.Universal, so lots of extra wire running all over engine bay needs to be routed and secured. Needs + battery connection.
Install< 15 Minutes, plug&play1+ Hour. Might require wire splicing
AppearanceLooks OEMMany separate parts / boxes / modules. Clearly aftermarket
Works with DRL (Pos 0)Not recommendedOK with antiflicker
Bulb Failure MessageKeeps factory functionality: “Bulb Failure: Low Beam” Message only when ballast or bulb actually fails.Always (no load resistors)

Never (w/load resistors) – even if one or both HIDs fail.

ProtectionKeeps original fuses & soft shutdownSeparate inline fuse. No soft shutdown
Price$100 from skbowe.comThe Retrofit Source ($45 – $80 1

I’m just including the relay harness for comparison here – although it will work, it’s a clunky, inelegant solution compared to the SKBOWE (ok, so maybe I’m biased?).

Decision #2 – Optics: Straight Rebase or Projector Swap, Mods

BMW E46 Bi-Xenon projector (left) vs the Volvo P1 OE Halogen H11 projector (right)
Replica E46 Bi-Xenon projector (left) vs the Volvo P1 OE Halogen H11 projector (right) [credit: nick0matic]
As Nick explained in detail, the “E46 projector” doesn’t really exist – it’s what we call the mounting pattern, 3″ lens size, and bowl dimension of the Bosch Automotive Lighting (AL) projector, a de facto standard that was first introduced on the BMW E46 3-series. Many OEMs have sourced from AL since then, and there have been many variants of bulb-base (D1S, D2S, D3S, Halogen), movable shield (bi-xenon), and focal length introduced over the two decades of use.

AL’s consistent dimensioning is a big reason why our stock halogens (also an “E46” variant) are so easy to swap out. Pretty much every headlight with an AL logo on it is using the “E46” standard in one form or another. However, not all of these projectors are created equal, and it is important to know what you are buying before you drop any cash.

The AL Projector Guide (V1). Full PDF here:

There are two generations of OEM AL projectors: Gen1 (the original “E46” projector) was in production up to around 2004 and used D2S bulbs held in with a black plastic retainer ring. As shown in the projector identification guide, they use a 3-wire solenoid to actuate the shield, and can’t be wired directly to your high-beam. The Gen2 projectors are the best optically, and can be wired straight to the high-beam. Replica projectors are copies of Gen1 housings and PCBs, with a 2-wire solenoid.

HID bulb types. Read more about them in this HIDPlanet thread. ECG is the technical name for ballast. All aftermarket ballasts are designed to use D1 and D2 bulbs only, and will not operate the other bulb types.

There are several factors to consider when looking at an AL projector:

  • Lens Size: There are two families of AL projectors, ones with 3″ lenses (like in our P1 Volvos) and ones with 2.5″ lenses (which don’t fit). The mounting hole pattern is different, so make sure you are getting a 3″ lens or it won’t bolt up at all. Even with an adapter plate, there will be an ugly gap around the shroud where you’ll see the lens frame.
  • Bulb (Holder): Different OEM and aftermarket “E46” pattern projectors come in a wide variety of bulb bases.  Your car comes with a halogen variants in either H11 or H7. HID variants include D1S/D2S and the newer mercury-free D3S/D4S (integrated ignitor / external ignitor, respectively). The D3/D4 bulb holders can be modified to accept D1/D2   bulbs, but you can’t mix D1/D2 ballasts with D3/D4 bulbs or vise versa. All aftermarket ballasts are designed for D1/D2 (or rebased) bulbs.
  • Reflector Material: Reflector bowls are made out of stamped steel, Silumin (Aluminum-silicon alloy), or high-temperature thermoplastic, before being flash PVD coated in aluminum. The Silumin bowls have the best durability because of their excellent heat dissipation and a very strong bowl-coating bond. Steel bowls (like the OEM halogen) are fairly durable but can develop dull patches at hotspots. High-end repos use aluminum bowls, while others use plastic which is the least durable, and are susceptible to large dull patches and burn through (speckling) which occurs when a piece of dust lands on the coating and heats up the coating behind it. There is no reliable way to clean a plastic reflector without permanent damage.
  • Shield Actuator: The shield is either fixed (halogen or xenon) or electromechanical actuated (bi-xenon). The actuator adds supplemental high-beam functionality to the projector. If you are going through through the trouble of swapping projectors, be sure to get a bi-xenon version! Make sure to get a 2-wire solenoid (see the projector guide) to avoid needing a controller.
  • Shield Shape: The shape of the shield determines the look of the “cutoff”, the line between dark and light that prevents you from blinding other drivers. The shield is typically stepped so that the passenger side throws farther than the driver side (to protect oncoming traffic) – so LHD and RHD projectors are not interchangeable. There are simple steps, vertical steps, and other “fancy” enhancements depending on the OEMs requirements. Shield mods usually involve fitting a curved shield, ensuring the entire edge is in focus for a sharp edge-to-edge cutoff.
  • Lens Style: OEM projector lenses are typically “decorated” – textured, frosted, or dimpled (sometimes incorrectly called fresnel, which is entirely different) – sometimes with horizontal lines to blur coloration at the cutoff. High end OEM (BMW) sometimes use clear lenses (e.g. ZKW), which have been reproduced (ZKW-R). Technically speaking, a clear lens will project a virtual image of the bulb and shield – including the shape of the arc (or filament) and edge diffraction at the shield cutoff. Texturing the lens is an application of non-imaging optics which effectively blurs these features, preventing any hard lines or hot spots. The light thrown down the road is the same.
  • Lens Material: The lens should be glass. Cheap aftermarket projectors occasionally use acrylic lenses, which are optically inferior and will not hold up well in heat.
  • Focal Length: Relevant only if you want to replace the lens, the focal length is the distance between the foci in the ellipsoidal reflector. It determines how far away the center of the arc/filament (F1) is from the focus of the biconvex lens (F2). The standard focal length is 22mm but some (like the P1 OEM Bi-Xenon) have a shorter focal length which results in a stubbier build and more convex lens shape. Lenses of different focal lengths are not interchangeable. The “rounder” (more convex) the lens is, the tighter the beam will be.
  • Lens Support: Relevant only if you want to replace the lens, the stamped-steel support that holds the lens at the correct distance to the reflector is fastened ether with screws or rivets. To replace the lens, you need to remove the support and the wire lens retaining ring. Screws are easier, as rivets must be drilled out before they can be replaced with nuts/bolts or new rivets.

A quick rundown comparing the options:

OEM Halogen AL + Rebased BulbAL Bi-Xenon “E46” Projector
DifficultyVery EasyModerate-High
InstallJust change the bulbRemove factory projector, install E46 projector, modify rear cap (1) (2) if using integrated ignitor, connect high-beam wiring. Clear lens might require drilling out rivets in lens retainer.
Usable Light Down RoadGoodBest
Bi-Xenon HighNoYes
Base Price$0$100-$200 (salvage – read this carefully) or $50-150 replica (lower quality)
(for either)
+ $40-$45 for clear lens (optional)

+ $8 for DIY shield mod (optional)

If you want to get fancy, there are mods you can do to both the OE or an “E46” AL projector. Going with a clear lens can clean up the cutoff some on either projector, and the shield mod (only with a clear lens) lets you change the cutoff color and shape. These are advanced topics so I won’t go into depth here, but Kyle’s thread on the subject is a great starting point, and the archive of the original JVXDriver shield mod guide is a classic.

Note on used projectors: Be very careful if you need to clean the optical surfaces. You need optical tissue and reagent-grade isopropyl to avoid damaging the coating or scratching the surface. See this guide on cleaning optics for instructions.

Wiring Re-Based Bulbs

The re-based bulb wiring is simple, as there is no high-beam solenoid. The power comes out of the stock headlight connector, and goes to the SKBOWE, and then the ballast. The ballast output goes to the ignitor (might be integrated inline) and then to the bulb.

The diagram below shows the configuration for Morimoto XB style ballasts with removable ignitors, but any other brand is much the same (just with fewer connectors, e.g. the input adapter, bulb, and grommet may be one piece).


Wiring Morimoto ballasts and rebased bulbs with the SKBOWE.
Wiring Morimoto ballasts and rebased bulbs with the SKBOWE. Thanks to Mr. Breakfast @ C30Crew for fixing my diagram.


Wiring Bi-Xenon Projectors

The “Bi-Xenon” feature of OEM-style AL projectors means that there is an electromechanical solenoid inside of the projector wired in parallel with the high-beam circuit, that physically displaces the shield within the projector to allow more light out.

Bi-Xenon projector operation

When you engage the high beams, the solenoid pulls the shield down towards the front of the projector, allowing light from the bottom of the reflector to pass through the top of the lens, sending it farther down the road.

Wiring the "E46" AL projector bi-xenon solenoid using using a 9005 extension
Wiring the “E46” AL projector bi-xenon solenoid using using a 9005 extension

For this to work, the solenoid must be wired in parallel with the 9005 (aka HB3) high-beam bulb. You can do this by cutting the stock high beam connector terminals off, and using new 9005 crimp terminals to emulate the OEM headlight wiring – see this how-to writeup on the “factory” wiring. An easier way is to use a 9005 extension and splice in the wires that come off of the projector using high quality butt connectors (Never use “t-taps” or “quick-taps”), I also have a  writeup on making this adapter.

Note that projector solenoids are polarized (meaning there is a + and a -)  because of the flyback diode which is mounted on the small circuit board. Use the projector identification guide to determine the correct hookup of your projectors.

Bi-Xenon projectors will likely have a D2S base bulb. You can use a native D2S kit (like the Morimoto), or a normal kit and AMP-D2S adapters. The iJdmToy D2S adapters fit under the cover having to cut it.

Install using morimoto ballasts 3 and 4-pin SuperSeal connectors to eliminate the need for a grommet, and allow the ignitor to easily be replaced.Super clean “nick-style” install for Morimoto ballasts using 3 and 4-pin SuperSeal connectors and a custom harness to eliminate the need for a grommet, and allow the ignitor to easily be replaced.

Optics Gallery

Gallery: Expand to see images of the various options. If you have pics and you’d like to share please drop me a note or post in one of the threads.

Rebased Bulb, Stock projector
E46 Projector Swap
E46 with shield mod

Decision #3 – HID Kit: 35W or 50W / Rebase or D2S / Color Temperature

Almost there! The final decision is which ballast kit to buy. Both the SKBOWE and Relay Harness options allow you to choose any HID brand and power you want, you don’t need to get a “CANBUS” specific kit or anything. Almost all vendors sell H11 or H7 rebased conversions, but not all ballast vendors sell D2S kits – so if you go down the Bi-Xenon (E46) route you’ll either need to find one that does or buy AMP-to-D2S adapters and D2S bulbs separately.

Power: 35W vs 50W

All automotive HID capsules (bulbs) are designed to be driven at 35W – there is no such thing as a 50W or 55W HID capsule. So 50W ballasts drive the 35W HID capsule at a higher power than it was designed for, increasing light output but decreasing life span2.

Halogen35W Ballast50W Ballast
Light Output (Lumens)1200 [1]
1350 [H11]
1400 [2]
2100 [H9]
2500 (Aftermarket)[1]
3200 [1][2][5]
3500 [4]
4000 [1]
4200 [4]
5000 [2][3]
Life span (Hours)125-250 (H11) [H11]
250 (H9) [8][H9]
550 (H11) [8] (H11 / H7)
1500-2000 (H11 LL)[7]
1000 hours
2000 hours[4]

Ballast Recommendations

I can recommend the following ballasts – this list may be updated as new ballasts are reviewed.

Note that I don’t get kickbacks from any of these sites. A lot of the parts can be obtained cheaper elsewhere (especially if you are not in the US). SKBOWEs have been proven to work with the kits from all of the vendors listed on this page, so I feel comfortable recommending them, but do shop around (e.g.  eBay) if price is a discouraging you from attempting a retrofit.

The SKBOWE will work with any ballast, but that does not mean that every kit is the same. As with most things, you get what you pay for, and ballasts/HID kits are no different. The less expensive kits might have mismatched bulbs, unstable arcs, and short lifespans.

Make sure to order an H11 or H7 kit to match the halogen bulbs in your car – this will ensure you have the correct connector inside the headlight. All aftermarket HID kits come with a 9005/9006 connector on the outside-the-headlight side that plugs into the ballast. The SKBOWE goes between the ballast end of the harness that passes through the headlight housing and the ballast. Both of these are 9005/9006 combo connectors.

35 Watt Ballast Options

50 Watt Ballast Options

  • Morimoto XB55 (AMP) – Everyone seems to love these. high quality, waterproof, reliable products.
  • DDM 55W Slim – Not the highest quality, but a great price and a lifetime warranty. The SKBOWE will run these just fine… You’re spending nearly $100 on the error eliminator so that you can use any brand of ballast, if you don’t mind replacing them every 2 years (for free), the DDMs are a great choice.
  • HID50’s ULTRA kit – My personal favorite. I have been using these in my car for nearly 8 years. Rock-solid dependable and very bright. Confirmed 5+ year life span. Located in the UK so shipping to the US can be cost-prohibitive.

Avoid These Kits

Many of the HID kits advertised to “work” with P1 cars have sub-optimal input filters and load resistors built in that waste power, and they are otherwise not noteworthy performers. Typically, they are successful because of low current draw (higher the current, the bigger a capacitor you need) which means low output. Without a SKBOWE or relay harness, they WILL fail prematurely and are a risk to the WMM. They will work with a SKBOWE or relay harness, but so will many other products of much higher quality.

  • DO NOT BUY: ProTuningLab CANBUS 35W kit – this has a built in canceler that is way undersized for the application and contains load resistors. Actual current draw is closer to 40W. It gets very hot during operation, and the light output is sub-par for a 35W ballasts.
  • DO NOT BUY: Any kit that costs less than $30. It will likely be rubbish.
  • DO NOT BUY Kensun H11 6000K – Recently several reports of quality issues with this brand, including unstable arc, inconsistent bulb color, and occasional misfires. As with any purchase, check reviews first!


Bulb Color Temperature (3000k, 4300K, 6000K, etc…)


HID Color temperature picture
HID color temperature comparison in real projectors (credit: TRS)

Color Temperature is a way to characterize the color of light by comparing it to an ideal black-body radiator heated to a specific temperature (measured in absolute degrees Kelvin). In general, lower temperatures will be more yellow, while higher temperatures will be more blue.

The brightest bulbs are in the 4300K-5500K range. Other color temperatures are achieved either by special halide mixes (good bulbs) or by dying the envelope (cheap bulbs – have a visible color when off) – both reduce the amount of light that a given power ballast can produce.

Remember that if you choose to go with an exotic color temperature, you are reducing the usability of your headlights..

Running a 35W bulb at 50W will decrease the color temperature (by about 1000K[4]) as more sodium disassociates from the metal halides in the bulb (pdf). So if you want OEM looking light with a 50W kit, choose 5000K bulbs.

TL;DR: Sample Configurations

I know that is a lot of info to digest, so I’ve put together some sample configurations to illustrate the process.

USA – Budget Rebase 50W Sample Configuration:

This is about the cheapest I’d recommend going for an HID conversion, works out to under $150 (as of 11/2017):
1) SKBOWE PWM filter = $100
2) Keep OEM halogen projectors = $0
3) DDM 55W HID kit: DDM (choose 55w + H11 bulbs) = $45
Total = $145

USA – Budget Bi-Xenon Sample Configuration:

Here is a sample configuration to get OEM Bi-Xenon projectors on you P1 for around $300 (as of 11/2017):
1) SKBOWE PWM filter = $100
2) Gen2 OEM Bi-Xenon projectors (eBay per the selection guide), or replicas (e.g. from TRS) = $75
3) DDM 35W HID kit: DDM (choose H11 bulbs) ($50) + iJdmToy D2S adapters ($15) + Ultra D2S bulbs ($35) = $110
Note that you need to order the HID kit in H11 to get the right grommet passthrough. You will not use the H11 bulbs, but need to take apart the connectors on the iJdmToy adapters and pass them through the grommet.



Once you have gathered up the parts for your HID retrofit, head on over to the P1 HID Install Guide


[1] https://www.diodedynamics.com/store/research-1/research-hid/hid-brightness.html
[2] http://www.hid50.com/50watt.html
[3] https://hidkitpros.com/wp-content/uploads/2013/05/35-vs-55-Watt-HID-Kit.pdf
[4] https://www.theretrofitsource.com/hid-systems/universal-kits/h11-morimoto-elite.html
[5] http://catalog.gelighting.com/lamp/automotive/front-lighting-discharge-automotive-headlight-lamp/d2s-lamps/f=d2s-basic/d=0/
[6] http://www.greenliteusa.com/en/shop/1743-d2s-35w-hid-headlight.html
[7] http://download.p4c.philips.com/files/1/12362llecoc1/12362llecoc1_pss_.pdf
[8] http://www.driveaccord.net/forums/138-audio-electronics-lighting/111066-conversion-oem-low-beam-h11-h9-halogen-bulb.html

[H7] https://www.osram-americas.com/en-us/applications/automotive-lighting-systems/Pages/lrgproductspecs.aspx?partnumber=H7
[H9] https://www.osram-americas.com/en-us/applications/automotive-lighting-systems/Pages/lrgproductspecs.aspx?partnumber=H9
[H11] https://www.osram-americas.com/en-us/applications/automotive-lighting-systems/Pages/lrgproductspecs.aspx?partnumber=H11


  1. From TRS: $45 – H11 relay harness + Antiflicker

    $35 – Load resistors (for no BOW): 2x kits of 2 resistors for 20w/side

  2. Note on lifespan: The lifespan of a halogen bulb is the average number of hours it can run before burning out – after which no light at all will come out. It’s actually very difficult to peg down the advertised life of a halogen bulb, due to many factors including nominal and peak voltage, vibration, temperature, etc, but I would feel comfortable saying somewhere around 1000 hours is typical for Volvo P1 cars since the headlight voltage is regulated and they have DRL during the daytime (greatly extending bulb life).

    Lumen maintenance curve for HID lamps

    Correctly manufactured (not leaking gas, etc) HID bulbs never really “burn out”, though they may degrade so badly that the ballasts can’t get them started. Instead, they loose brightness with time. When a OE (Phillips, GE, Osram) lists an HID capsule lifespan, this is the number of hours before the output falls bellow the minimum rated lumens (usually around 3200) – the bulbs start off much higher. Aftermarket manufactures might higher lumens by picking the initial brightness, or longer lifespans by allowing a greater percentage degradation, but they are really all following the same curve.

    While many HID bulbs are rated at crazy numbers (like 2000+ hours), you’ll only get maximum light out of them for the first 200 hours or so (around 85% of original light output), and less if you run 50W ballasts. I am a usable-light-down-range nut, and with 50W ballasts I replace my bulbs once per year (I don’t drive much: ~5k miles / average 25 mph ~= 200 hours).