Changing Bulbs in 355/348 3rd Brake Light (pictorial)

There's been some debate on how to change the bulbs, as well as which bulbs to use, for the 7 lights in the third brake light on 348's and 355's (i.e. the top rear engine bonnet exterior light-fixture).

Apparently, some 355's need to drill out two rivets. Let me state that is not necessary for the 1994 348 Spider (and probably not required for most 348/355 models).

The first picture below shows all of what you will need: Type 74 bulbs (push fit, not twist fit), flat blade screw driver, phillips screwdriver, 2.5mm allen wrench.
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OK, you've got your tools and supplies. Now pop your engine bonnet and insert your 2.5mm allen wrench into each of the two screws that hold the black cover beneath your 3rd brake light fixture (see pictures below).
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With the black cover removed, follow the arrow in the picture by sliding the third brake light fixture over to the right. That will let it drop down at an angle and then be able to be pulled completely out.
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With your light out of the bonnet, squeeze together the black plastic electrical connector on the back to allow you to pull it out of the light fixture.
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If desired, use your phillips to unscrew the two brackets (not required).
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Now use your flathead screwdriver to *gently* pry apart the plastic backing to reveal your bulbs.
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^^^ Picture was obviously taken during the Gumball run, right ????


(HAHAHA, I kill myself with my lame humor)

 

Remove your bad bulbs (typically black on top of the glass) and insert your new "74" bulbs.
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Now resinsert your 3rd brake light fixture (if you removed the brackets, re-install them and then reinsert your 3rd brake light).

TIP: handscrew your two allen screws just a bit so that you can move your black cover and 3rd brake light simultaneously with one hand, then tighten with your 2.5mm allen wrench with one hand while holding the 3rd brake light fixture as close to the edge of your bonnet cutout as possible (this makes your light appear to be closer to "flush" than if you let it be more recessed back into your engine bonnet cover).

To view your seven third brake light bulbs on, you've got to completely close your engine cover bonnet (this makes the ground contact to close the circuit).

You'll need something or someone to depress your brake pedal with the ignition key switched to Run (not Start).

After following all of the above steps, you'll go from this:
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To this:


(total time: 7 minutes)
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NOTE: If you'll look at the light fixture in post #6 above, keep in mind that the black plastic back that you are prying off (gently) will only go back on one way...so don't try to force it.

If you think that you have to use force to get it to snap back together, then STOP!

Turn the plastic back upside down and try gently squeezing it back together.

It goes back together easily, no force of any note required, so don't break your brake light!

 

NOTE: if you want to use more modern LEDs (they draw less current from your alternator/battery, emit less heat, last forever) instead of ancient #74 bulbs, then this LED should suffice: http://www.aceparts.co.uk/product_info.php/cPath/52/products_id/97


Now would also be a good time to spray some corrosion block, contact cleaner, and/or stabilant 22a onto your hidden 3rd brake light metallic electrical connections as well as onto your bonnet ground pin.
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Another source for Type 74 LED's is here: http://www.superbrightleds.com/1157.htm

Also, post #2 above should overtly mention to unscrew the two (2.5mm) allen screws in order to remove the black cover panel.

 

How was the intensity after the conversion? I'm curious, as the bulbs I took out of my 355 third brake light were marked 2.3 watt, which is the same spec as a Sylvania 2723. It has been previously posted that the Hella 3rd brake light housing on the 348 is marked "12 volt, 1,5 cp", which translates to 1.5 candlepower.
http://www.ferrarichat.com/forum/showpost.php?p=134608981&postcount=7

I never looked that closely at the Hella housing on my 355, but did save the bulbs, which are marked with "2,3" on them.

The Sylvania 74 bulb you mention is only rated at .7 candlepower which is half the rated output specified. In other words, I am suspecting the 348 uses the same bulb as the 355, which is the 2723, not the 74. For some reason, the specs on the 74 and 2723 are not using the same rating system, and I am uncertain of the conversion, as it appears one cannot simply convert cp to watts.

What is the output of the LED bulbs?

 

Nice work again No Doubt

Nice enough to put a horn on a jelly fish

 

What you say above jives with what I saw, that the 74's aren't quite as bright as the 2723, but they are pretty similar to the LED intensity.

I used the 74's for about a week, then my LED's arrived and I switched.

I ended up using the LED's in all 6 of the 348's top level running lights, as well as using LED's for all of the center high-mounted brake light.

But the LED's were not bright enough to work as the two main lower brake lights, and the LED's didn't have enough light spread from far left and far right views to function as brake lights.

As running lights the LED's are great. As center brake lights, they are great.

The really amazing thing is that the LED's in the high center brake light illuminate at least a full tenth of a second quicker than do the lower brake bulbs.

So the best of both worlds are the fast-lighting center high mount brake LED's combined with the brighter, wider-light-casting lower brake bulbs.

The old style light bulbs are brighter, but they have to heat up before they can light up, and they have to cool down before their light turns off.

When you compare them side by side to the LED's, the LED's light up quicker and go dark faster than do the old bulbs.

 

Interesting stuff. You might want to update your webpage on what the correct replacement bulb is for the 348 third brake light then, as it states it is the 74, and not the 2723.

The faster response of LED's is nice, but not sure I am sold on the reduced intensity and reduced angle of light. I think I will stick with the stock bulbs. After 7+ years I had one of the seven burn out, replaced all 7, so should be good for another 7 years...which should more than cover my ownership time...

 

none of mine work, wonder if its just all 7 bulbs. Good write up though, will likely tackle this one next soon as I sort on my other light issues.

 

Your engine lid must be closed for the 3rd brake lights to work.

What's the background on the 348 that you acquired?

 

I was looking at some lighting issues last night and found that the left rear side
marker wasn't working. I figured it was a bulb but I found that it was
disconnected at the two wire connector. Don't know why, but I reconnected
it and it is working now.

I also found another two wire connector disconnected up by the bumper (rear)
colors are ylw/red blk/grn on one connector (bullet type) and the other is
blk and rd.
any body know what that is for I couldn't trace past the harness.
thanks,

 

Just as an update, after using the Superbright LEDs for three years, I've had two of the third brake light LEDs fail (out of 7 that are in that 3rd brake light fixture). Also, two of the red 1156 LEDs failed in my driving lights (the 348 has 6 of those rear driving lights) after two years. One of the failed 1156 LEDs would flash half of its lights intermittantly.

But in all fairness, I've also had an 1156LL (long-life!) incandescent bulb fail in one of my main two brake lights in this same amount of time (both installed on my 348 at the same time as my LEDs). It was marked "Made in China." Needless to say it wasn't "Long Life".

 

Thanks to this thread, I was able to change one of my burnt out bulbs.

I tried before, I was able to remove the entire fixture from the engine bonnet, but couldn't figure out how to pry loose the assembly and didn't want to break anything.

Nice job No Doubt, thanks again.

 

Great to hear Mike!

 

Well I followed instructions (they are great by the way) has I thought my bulbs were bad and purchased the Super Bright LED's (74). All went smoothly, removal, splitting up, placing new LED's in and insertion back. Unfortunately I must have something else going on... Third break light still not working after closing the lid? ARGHH!

Anyone else know where else I could look around to see why it is not "connecting"?

 

Check the fuse and then check that the pop up pin under the hood is clean and making good contact.