2008 DTS Headlight assembly bulbs

[mike33]

Hi Team, I will be replacing headlight bulb in my 2008 DTS this weekend. I want to replace all three bulbs (headlight, turn signal, little mystery bulb)

What is the part # on that third little bulb? Looks like a 194, but is not?

Thanks in advance! Mike

[Cadillac Jim]

The FSM is not clear about the "little third bulb" and doesn't have part or bulb numbers, as it's a technician's resource for work instructions, not a parts list, and it doesn't include parts lists. There are three groups of schematics and instructions, with sub-levels, under Lighting, Schematic and Routing Diagrams:

• Headlights/Daytime Running Lights (DRL) Schematics
  • Headlamps (apparently only high/low beam bulbs and circuits here), circuit appears to include a four-terminal static-sensitive element that is probably a module and a low beam (PWM dimming for running lights?)
  • Headlamp switch (just signals to the BCM, which controls everything with relays).
• Fog Lights Schematics (very simple, one diagram, switch signals BCM, BCM grounds relay which powers two bulbs)
• Exterior Lights Schematics
  • Front Park, Marker, Position Lamps (includes Position Lamp and Parking Lamp, and Marker LED connected to Parking Lamp, all in the headlight assembly)
  • Rear Park and Tail Lamps
  • License Lamps
  • Front Turn Signal/Hazard Lamps (The LEDs in the outside rear-view mirrors are here!)
  • Cornering Lamps
  • Stop/Rear Turn Signal Lamps
  • Center High-Mounted Stop Lamp
  • Backup Lamps
• Interior Lights Schematics (lots of things here)
• Interior Lights Dimming Schematics (lots of things here)

I would guess that the "third little bulb" is the Position Lamp.

The Osram Sylvania Lamp Replacement Guide for your car is here:

http://www.sylvania.com/en-us/applications/automotive-lighting-systems/Pages/lrgallbulbs.aspx?year=2008&qual=&model=669&make=17

• The headlight is apparently a HID bulb, number D15.
• Parking lamps are listed as number 4157NA or 2825, which goes where is ambiguous. The 2825 is a tubular bulb with a miniature base and is amber, notwithstanding the photo on Amazon. The 4157NA is a round bulb like old conventional parking/stop light bulbs but with a rectangular black plastic connector base; it's also amber.
• A lot of small bulbs are listed all as number 194, so that's my best guess for the "third little bulb."

The Sylvania page on the 194 is HERE (long link).

Amazon page on a pack of 10 194's for $8: http://www.amazon.com/Sylvania-Bulb-194-Pack-Bulbs/dp/B002PDRDOQ

Amazon page on the 2825 is http://www.amazon.com/Sylvania-2825-Miniature-Lamp-Pack/dp/B000J2JE0G

Amazon page on the 4157NA is http://www.amazon.com/Sylvania-3157NA-4157NA-Miniature-Natural/dp/B000COCUF2

You can replace the little bulb with an LED equivalent using a crossover from Sylvania or others if you like.

[mike33]

Thank you for that response. I was reading there is a risk of electrical shock when changing the xenon HID bulb.? Anyone do one before and not get shocked?

[Cadillac Jim]

Make sure that the car is off at lest a half hour. The best time is Saturday morning, after it has been sitting overnight.

[Texas Jim]

Thank you for that response. I was reading there is a risk of electrical shock when changing the xenon HID bulb.? Anyone do one before and not get shocked?

Several guys on the other forum have replaced the HID bulbs... this is the first time I have heard of a potential shock hazard.

[Cadillac Jim]

I haven't heard of a shock hazard warning either. If there is one, it will be on the bulb packaging and probably on the headlamp.

The way HID works is a capacitive-discharge spark from the ignitor that fires off the bulb, then a current-controlled driver that keeps it on. Either can provide a shock. If the car is turned off, and the negative battery cable disconnected, the capacitive-discharge spark generator still has a charge saved up for the next ignition. That will bleed down slowly, perhaps *very* slowly. In the unlikely event that the ignitor trigger comes through somehow, say by a static discharge from handling getting into the wiring harness, then the ignitor pulse could come through with anywhere from full strength to almost nothing, depending on how much charge is still on the capacitor.

If the ignitor is not a CDI type, there is no shock hazard with the battery disconnected. But I do believe that just about all automotive HDI ignitors are the CDI type because they are simpler, more reliable, and draw a whole lot less power than the other type. The other type is a points-and-condenser-with-coil-as-transformer type, like distributor-type ignition systems; good when you are generating a lot of sparks but must be switched on and off if you just want one, and they draw a lot of current.

[mike33]

Thanks for the responses. I went ahead and completed the job this morning. It went well. I used bulbs D1S, 5702AK and 2825.

I disconnected the neg on the battery just to be safe. This is about a $470.00 job at the dealer (parts and labor). So, very nice to save the money! I bought a rivet puller to help with all the plastic rivets and also followed this video:

http://www.carcarekiosk.com/video/2009_Cadillac_DTS_Platinum_4.6L_V8/lights/headlight

Thanks, Mike

[Texas Jim]

Good job...

[airmike]

That is an excellent video. How much did it cost you to do that yourself? You should write yourself a check

[mike33]

Thanks Gentlemen. It was $79+1.00+0.50= $80.50 for bulbs and I think $12.00for rivet tool (not a bad investment, I never broke one single rivet)

Dealer price for bulbs would have been $300+$20+$7 and about $150 labor. I appreciate this board, and glad I can contribute occasionally.

[KHE]

Were all three lights burned out?

[mike33]

Hi KHE, nope only the HID was burned out. But, since this is a 2.5 hr project, you bet I'm gonna replace every bulb I can at that time!