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79 Eldorado Biarritz: Instrumentation Light Intensity

Started by 79 Eldorado, November 02, 2018, 10:59:12 AM

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79 Eldorado

I thought I read somewhere the instrumentation lighting on these cars was not as bright as one would typically think it should be. Mine is not terrible but it seems like it should be a little brighter.

One friend suggested it could be the quality of the ground. I did look in the Electrical trouble shooting manual and it seems there are 2 grounds for the instrumentation. I suppose it could also be the way ground is pushed into contact; plugs on the back of the instrument panel.

If there isn't an issue there I was wondering if anyone has replaced a couple of the 194 bulbs with 168's. The 168 is normally more intense but doesn't last as long. However long life versions of the 168 are available. Because the dash lights are on a dimmer I thought avoiding LED would be best because I've had mixed results with LED's and dimmers. I assume the 168's draw more current and so I was also wondering if it is significant enough to cause an issue with the laminate wiring etc.

My dash is still apart now so I will likely change the bulbs now but I was wondering if I should try to improve the lighting while I'm working on it.

Any thoughts?

Thanks,
Scott

79 Eldorado

I checked all of the lights in the instrument cluster and only one was burned out. Several were not making good contact with their sockets though so perhaps that's why things were dim.

So the bulb which was burned out was neither a 194 nor a 168. In fact I don't know what it is and I'm hoping someone can help identify it. The style is the same as the 194/168 but the diameter is about 1/2 of the others. I'm planning to go to the auto parts store but I thought I would ask here. The markings are gone on both the burned out one and the only other of the same type.

I am showing the bulb/ socket, the location and a close-up of the location.

Thanks,
Scott

chrisntam

The factory service manual should provide the bulb numbers, maybe even the owners manual.  Some are using LED bulbs, but I have no idea of one is made with the 194/168 base.
1970 Deville Convertible 
Dallas, Texas

Eric DeVirgilis CLC# 8621

LED replacements usually don't respond well to reducing the voltage for dimming which is how it is done with incandescent lamps.

In other words if the LEDs are too bright, they might not dim very much.
A Cadillac Motorcar is a Possession for which there is no Acceptable Substitute

79 Eldorado

One of the guys at the local Autozone who sometimes has a late 70's /early 80's car answered the phone and he was able to look it up in a paper catalog. What he found has the correct base. The top is a little more "bulbous" but it looks like it is likely a proper replacement. The one he found was a Sylvania 24 and they had them in stock.

I've got all of the manuals so I can check later to see if the bulb number is identified. At 14V this one is listed as 3.4W.

Thanks for the replies,
Scott

79 Eldorado

The 24 fits in the socket but the bulbous tip is too large to fit through the insertion area. So I installed the socket without the bulb and I was able to install the bulb from the opposite side. Small area and not super easy to align but it's in and it's about the intensity of the remaining neighboring original.

I started to go through the service manual and have not found a section identifying the lamp nrs yet. I don't have the owners manual with me. I didn't check the Electrical Trouble shooting manual yet either.

Interesting if that 24 is the proper one Sylvania made a design change which at least is not a perfect solution for 79 Eldorado... Anyway it functions.

Scott

Cape Cod Fleetwood

The problem could be your headlamp switch too.
Next year, 2020, when I start working inside The Ark *ALL* the interior lights are
being replaced with LED, I can't see inside the car at night at all. Especially the dash.
If I'm passing other cars, I guess I'm going fast enough, I can't see the dash. I'll be
replacing the headlamp switch (already in stock), cleaning the back of the displays,
and changing to LED.

\m/
Laurie
There are 2 kinds of cars in the world, Cadillac and everything else....

The Present -1970 Fleetwood Brougham

The Past -
1996 Deville Concours
1987 Sedan De Ville "Commonwealth Edition"
1981 Coupe De Ville (8-6-4)
1976 Sedan De Ville
1975 Sedan De Ville

The Daily Driver and work slave -
2008 GMC Acadia SLT *options/all

79 Eldorado

Laurie,
I decided against LED's because I've had a few LED's which didn't dim well (house not car). I did finally find a Phillips LED which works pretty well with the dimmer in the house. On the Cadillac I think my intensity was due to some bulbs being out. I replied to my original thread because I came across these other bulbs in the instrumentation cluster. Everything was either 168 or 194 except these two. Not all of the writing on the bulbs is still visible but I did notice some of the holders are black and some grey. I suspected that possibly they did that as a strategic thing to go with the different bulb nr but they interchange just like the bulbs. I've had trouble before with this type of bulb making good contact. They are the style with the looped wire as the contact. On a license plate bulb I added some solder to one of the wires. Anyway they're all working at least for now.

Scott

Eric DeVirgilis CLC# 8621

I agree with the decision to remain with OEM lamps. A fresh set of new bulbs, and just as importantly, a cleaning of the lenses should restore the dash illumination to its original brightness. This is especially true of cars that had been smoked in.
A Cadillac Motorcar is a Possession for which there is no Acceptable Substitute

79 Eldorado

Update: According to the Service Manual the bulb I was trying to find should a 161. I ordered some Sylvania 161 bulbs and the package was labeled 161 but the bulbs inside were the same size as 168's and 194's??!! Because I knew I ordered the correct number and the package was labeled properly I didn't even look at them before opening it. Of course no way would the replacement fit.

The bulb turned out to be the fuel economy indicator 1 of 2. The one which was out is the one which shows that you are getting good fuel economy. The tell tale light mask area is green. The one which was still functioning was the one for poor fuel economy (amber tell tale mask). I moved the 24 bulb to the Amber position and the original functioning 161 to the green position.

Also once I cleaned the socket area of all of the bulbs they all worked and what a difference. I guess the answer to my original question is leave all of the recommended bulbs in place because if they are all working in no way is there any issue with the intensity. I took a picture for all to see which also shows the green dot in the lower left corner with the original 161 bulb.

I guess one more question: Is the service manual wrong, did Sylvania pack the wrong bulbs in the correct package or did they make a reproduction which isn't compatible with the original (so as far as they know the larger bulb is correct)?

Scott