S4 Instrument light bulbs

**DavidH** · #1 (**permalink**) 11-02-2009, 01:33 PM

After 19 years, a couple of gauge bulbs winked out in my 91 S4; so I am going to replace all of them. I went to the local auto parts store and found that they have four different bulbs that will fit into the little bulb holders that attach to the back of the gauges. All four of them have same base and are the same physical size, but they each have different wattage and voltage. So, which ones should I buy in order to get the most light without doing some unintended damage to the gauge cluster (such as melting or shorting it)?

Sylvania part #73 - 14volts/1.1watts
Sylvania part #74 - 14v/1.4w
Sylvania part #2721 - 6.5v/9.8w
Sylvania part #2723 - 13.5v/2.3w

**Gubi** · #2 (**permalink**) 11-02-2009, 02:10 PM

The correct bulbs are the Sylvania "European Lamp" 2721. But you've got the wrong voltage & wattage listed there: they should be 1.2W and either 12 or 14V.

**DavidH** · #3 (**permalink**) 11-02-2009, 02:21 PM

Tom, Thanks. I could very well have written the spec down wrong. I was crouching on the floor at Autozone in front of the bulb rack, typing the info into my phone, all while the clerk was hovering over me sure he had found a Pep Boys spy.

**Tifosi** · #4 (**permalink**) 11-02-2009, 03:08 PM

Mabe he just thought you had sexy ears and wanted to put something in one.

Kilgore Trout · #5 (**permalink**) 11-02-2009, 03:10 PM

I've been using the Sylvania #74 in both my S3 and S4 Spiders for years without any issues. I bought a box of 20 at a NAPA store, and saved a bunch buying them that way. The bubble-pack ones sold by the pair are much more expensive.

**Tifosi** · #6 (**permalink**) 11-02-2009, 03:22 PM

One might get away with going to a junkyard and pawing through a mid-70's up through late 80's Ford dashboard.

There's better than a dozen in there for like free.

**DavidH** · #7 (**permalink**) 11-02-2009, 04:23 PM

Uh, Tom Gubi, I dropped by the parts store on the way home from work and grabbed a package of Sylvania #2721LL ("long life") bulbs. Right there on the package it says "6.5V/9.8W". Have they change things since the last time you put in new bulbs? Hmmm.

**Vintre** · #8 (**permalink**) 11-02-2009, 04:34 PM

Quote:

Originally Posted by DavidH

Uh, Tom Gubi, I dropped by the parts store on the way home from work and grabbed a package of Sylvania #2721LL ("long life") bulbs. Right there on the package it says "6.5V/9.8W". Have they change things since the last time you put in new bulbs? Hmmm.

**Tifosi** · #9 (**permalink**) 11-02-2009, 06:40 PM

Tangent on the 'LL' bulbs:

Over the past 2-3 tears I've bought them for various uses and postions in a few different cars. Always the correct wattage and voltage for the given location.

The only 'long life' I've seen out of any of them is that they last like a week and a half longer than their conventional (and cheaper) counterparts. (EG: reverse lights on the missus' car. Normally it's a pair a year. w/LL, it went a year and 2 weeks. I know this onnaconna changes are normally done right around the annual state safety inspection)

Never again will I bother with them things. However if I could find some quality LED bulbs that didn't cost an arm and a leg, I'd be willing to give that route a try as I know LEDs will last for infinitely longer than a conventional incadecent bulb, as long as they aren't over-volted.

**Gubi** · #10 (**permalink**) 11-02-2009, 06:57 PM

I'm not sure what you bought, but 6.5V/9.8W definitely isn't right. As far as I know the 2721 doesn't come in a long life version.

Here's what you should have. I bought these sometime in the past year.

**Tifosi** · #11 (**permalink**) 11-02-2009, 07:15 PM

All I find for it web-wide (well, as far as the search engine I was using would dig up using sylvania 2721 as the keyword) is: SYLVANIA Bulb 12V - 1.2W (2721)

No other wattages shown, and no LL types indicated.

Dunno. I can see where an LL might come onto market, but the wattage would almost assuredly remain the same, otherwise it'd end up with a different p#

**DavidH** · #12 (**permalink**) 11-02-2009, 07:28 PM

Tom, I'll see your green Sylvania package and raise you a red Sylvania package.
Hmmm again.
You, too, Darren.

**Tifosi** · #13 (**permalink**) 11-02-2009, 07:31 PM

Well ain't that special.

You gotted them where?

**Tifosi** · #14 (**permalink**) 11-02-2009, 07:35 PM

At 6.5V giving 9.8W, they gotta be stupid bright when 12V is put to them aren't they?

12V = 185% of 6.5V
9.8W x 185% = 18.13W

(that is if wattage goes up in direct proportion to increases in voltage of course)

**DavidH** · #15 (**permalink**) 11-02-2009, 07:39 PM

Got them at Autozone.
Darren, Would your arithmetic result in a lot of added heat, too? Like ruin-the-plastic-instrument-cluster heat?