Antenna ring and ECC bulbs - 2006 V70 AWD

Post by **scot850** » 17 Mar 2026, 21:02

I would like to buy new bulbs for these units. Volvo parts sites are not consistent on this, but Skandix and IPD seen to concur:

If you have ECC -

1) You need 2 x white based bulb holder and bulb - Part # 30739356

2) You need 4 x grey based bulb holder and bulb - Part # 30739358

Antenna ring:

1) You need 1 x black based bulb holder and bulb - Part # 30739357

Now, other than the different base colors, all the bulbs have blue gel covers on them and physically look the same. I cannot find any spec for the actual bulbs to know if they have different out puts, or which bulbs are fitted where in the ECC unit. I took then all out before finding they had different bases. I'd just assumed (wrongly) it was down to aftermarket bulbs perhaps being used.

I do know that the base color can make a difference to how bright the bulb shines so having them in the correct space is likely important.

Volvo here in Canada on-line sell each of these bulb for $20 EACH!!! That does not include 13% tax and shipping. So likely close to $120 or more US for 7 T4.2 bulbs!!

Can anyone help with:

1) Identifying the bulb outputs

2) A source for these bulbs (not necessarily with the blue gels) that are not as stupidly expensive? I know Digikey and the likes can supply bulbs and bulbs with bases, but not much good if I don't know the output of the bulbs.

I have seen these bulbs with 12 or 14V quoted and anywhere from 0.39 to 1.2W output.

Any help with yet another unnecessary stupid Volvo task would be much appreciated!

Thanks,

Neil.

Post by **matthew1** » 17 Mar 2026, 22:36

Maybe the 100% amazing Volvo Bulb Guide will help...

Post by **scot850** » 17 Mar 2026, 23:44

I had totally forgotten about this listing. However, good as it is, it does show these bulb part numbers and other than the base size for one which I don't understand (it measures as 10mm for all 3), it gives they are 12V (which I knew) but no Wattage is given. It probably is not too big a deal for the heater controls, but the antenna ring does throw a code like others that are monitored (like headlights bulbs when out of spec, or burnt out).

Neil.

Post by **scot850** » 19 Mar 2026, 15:22

So, I tried a resistance test to check the bulbs were good. The buzz out with different results. I don't have a working antenna bulb to test. However, here is a test for you electrical genius's!

Is there a way to work out the wattage of a bulb knowing only the resistance and the voltage?

If we assume the voltage is 12V, one of the 2 bulbs (need to check again which is which) gave a consistent 10-11 ohms and the other measured at 16 ohms consistently. Been a long time since I did any electrical stuff like that (40+ years!!).

Thanks,

Neil.

Post by **matthew1** » 19 Mar 2026, 16:25

AI tells me...

The formula comes from combining Ohm's Law (V = I × R) with the basic power formula (P = V × I):

Substitute I = V / R into P = V × I:

P = V × (V / R) = V² / R

So the power in watts is:

P = V² / R

Where:

P = power (watts, W)
V = voltage (volts, V)
R = resistance (ohms, Ω)

Post by **scot850** » 19 Mar 2026, 17:33

You are 100% correct. The only issue here is that many of these Neo wedge type bulbs can be rated at 12 or 14V which makes a huge difference to the calculation. That will make a large difference to the wattage/brightness of the bulbs.

I asked Volvo locally if they have any further info on the bulb details but unfortunately not.

Unfortunately I may have to buy one of each to confirm the bulb resistances. Expensive test! But even that is not helpful as the Voltage rating is still not known.

Neil.

Post by **cn90** » 19 Mar 2026, 19:28

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According to the YouTuber that posted the video above, the bulb he used was...

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Post by **cn90** » 19 Mar 2026, 19:35

Likely same wattage as that famous discussion on Radio Shack tiny bulbs used in radio lights in P80 cars.

Post by **scot850** » 19 Mar 2026, 23:12

I know what the part number is, and the Skandix bulb will work out as expensive as it would be from Volvo, or actually more due to there minimum shipping charges. Thank you anyway.

The issue is I want to find cheaper alternates to the crazy Volvo prices. However, no one seems to have any idea what the bulb specs for voltage and watts are, even the Volvo dealers. They are an incandescent bulb, so can't use a LED in the antenna as it hat to resistance match the expected value or it trips a warning. I refuse to pay the exorbitant price Volvo want for one bulb, especially as I need 7 and ideally 2 more for spare antenna rings I have. I'd rather buy some random bulbs for the heating control unit as they are less critical as they are not monitored. However, ideally I'd like them to match. I have found a variety of T4.2 bulbs with the bases, but the base color of the mounts are not the same. I'd like to find a suitable bulb and reuse the bases. Once I get this figured out, I can post my findings for others to take advantage of and save money.

Neil.

Post by **cn90** » 20 Mar 2026, 08:29

I told you the cheaper alternative bulb option above...if you search forum, you will see the Radio Shack bulb spec. Then find the equivalent bulb online or locally. About $1-$2 on eBay etc.

Or find radio/instrument cluster bulbs from local junk yard.

Also, I posted the spec on Honda instrument bulb in the P80 forum in the past, it is cheaper from Honda. Same bulb.

Another option is ignore it. You know where the ignition tumbler location is, even at night.