Tiny Interior Light Bulbs

[Beater400E]

You know the ones. The little guys hiding out inside the HVAC vents and the headlight switch. The originals are frosted white.

The commonly stated replacement is a 2721 bulb, but those are not frosted and are 1.2 watt bulbs. I have one of those in my headlight switch and it's way too bright and even hot.

I haven't had much luck finding a part number for the bulbs in the vents. Those appear to be frosted and have no plastic base. I'm not certain whether those are 0.4 watts, or maybe the more common 1.2 watts.

The headlight switch appears to be 0.4 watts with the plastic base.

Regardless... what is the consensus on those little bulbs? What are people using in each location?

 

[doolar]

Search for ”T5 0,4w bulbs” and you’ll find them. They are hard to find frosted, but in my experience it doesn’t make a huge difference.

The most important thing is to not use the 1,2w bulbs, they will be to warm and may melt the holder or surroundings. Or just make the plastic brittle fast.

I believe the gear position bulb is a 1,2w, but I’m not sure. All the other interior T5 bulbs are 0,4w.

Example:

10 x 12V 12-15V 30mA 0,4W T5 / Lampe / Miniature Bulb Glassockel Wedge W2x4.6d | eBay UK

Lamp Type: Wedge / Glassockel. Lamp Size: T5 / W2x4.6d. Diese sind nicht für die Verwendung im Haushalt geeignet und dürfen z.B. nicht als Raumbeleuchtung verwendet werden. Reparaturen an elektrischen Geräten sind gefährlich und dürfen nur von Fachpersonen durchgeführt werden!

www.ebay.co.uk

 

[gsxr]

@doolar is correct. I believe the 0.4w are used for most dashboard illumination (vents, headlight switch). The 1.2w are for the instrument cluster warning indicators and shifter illumination. MB numbers below:

000000-001061 = 0.4w
072601-012230 = 1.2w

Above numbers supercede previous numbers. Current numbers may have a -64 suffix. When looking at RevParts, remember that "Currently Unavailable" does not mean "NLA". Frosted has been NLA for many years. Poking around the EPC you'll find which ones are used in each location. Generally available much cheaper aftermarket vs from the dealer.

 

[Beater400E]

Search for ”T5 0.4w bulbs” and you'll find them. They are hard to find frosted, but in my experience it doesn't make a huge difference.

The most important thing is not to use the 1.2w bulbs, they will be too warm and may melt the holder or surroundings. Or just make the plastic brittle fast.

I believe the gear position bulb is a 1.2w, but I'm not sure. All the other interior T5 bulbs are 0.4w.

Example:

https://www.ebay.co.uk/itm/11227158...Zg&keyword=t5+0,4w&sacat=0&relatedSearch=true

That's a great solution. Strangely, that doesn't ship to the United States. I tried searching for the same or similar and have not been able to find anything just yet.

It's odd that those are listed as T5. They are actually not T5 bulbs. They use the same wedge base as a T5, but are actually a T1-1/2 or T1-3/4. Much smaller diameter.

Bulb sizing is weird. Wedge base bulb T sizes work by multiplying the T number by 1/8th of an inch to get the diameter of the bulb. A T5 bulb would therefore be 5/8 of an inch in diameter, or roughly 16mm. With that said, you are correct rhat any bulb with a T5 base is often marketed as a T5 bulb. Frustrating.

 

[dreaming.haze]

Mercedes-Benz Bulb (12V - 0.5W) Clear with Grey Socket Base 6924 - JAHN - these are what I have used in the past. 0,5w feels like a small step up that hopefully won't melt anything compared to the 1,2w bulbs.

Certainly not going to pay >$8 for one of the factory bulbs on ebay: New Genuine Mercedes-Benz Bulb / N 000000-001061 OEM | eBay

 

[Beater400E]

Mercedes-Benz Bulb (12V - 0.5W) Clear with Grey Socket Base 6924 - JAHN - these are what I have used in the past. 0,5w feels like a small step up that hopefully won't melt anything compared to the 1,2w bulbs.

Certainly not going to pay >$8 for one of the factory bulbs on ebay: New Genuine Mercedes-Benz Bulb / N 000000-001061 OEM | eBay

Yeah, I've seen the OE bulbs out there, but I'm wanting to grab a dozen or more bulbs so I have what I need for now and hopefully for the future. That JAHN bulb looks like a great option. I don't remember; the bulb comes right out of the plastic base for applications that don't need that socket, right?

 

[gsxr]

Be careful with the plastic-base bulbs. Those may not fit in the holders for some locations (I forget which).

eBay seller is including shipping and fees in the cost, so their price is nuts. Dealer MSRP is $3.40 each (still expensive), about $2.50 from discount dealers. Dealer superceded number appears to be a plastic-base type. I haven't tried to locate 0.4w/0.5w all-glass aftermarket versions.

 

[Beater400E]

Be careful with the plastic-base bulbs. Those may not fit in the holders for some locations (I forget which).

From memory... I want to say the plastic base bulb was only used in the headlight switch. All the rest are glass only I think. I could be wrong about that.

I know a lot of people use the 1.2w 2721 bulbs in the vent illumination and ash tray. I would guess that those would be OK, and I'll probably use those in all locations except the headlight switch.

I discovered something else last night that may have made my concern greater than it might have needed to be. The bulbs I'd used in the past for these applications were not 1.2w like I thought. They were 3w. So when I said the bulb in my headlight switch was too bright and hot... yeah that was a 3w bulb. Oops.

 

[Beater400E]

I don't remember; the bulb comes right out of the plastic base for applications that don't need that socket, right?

Answering my own question here. No. The bulb does not come out of the plastic base. I mean, you can remove it, but it doesn't have a wedge base so you can't just plug it into a wedge socket.

This is a Jahn 6924:



So at this point I think what I'll probably use is Hella 2721 in every position EXCEPT the headlight switch, and I'll use the Jahn 6924 in the headlight switch.