: Illuminated Thermometer on Mirror

04-18-05, 07:05 AM
I have a 1977 Coupe De Ville with the illuminated thermometer on the driver's door mirror. It has a fiber optic tube leading from a light bulb to the thermometer to light it up when the headlights are on. Problem is, the bulb is burnt out, and I can't find it to save my life. I traced the fiber optic tube several times, and it gets lost in wire harnesses up in the dash, and I gave up until I found this forum. Does anyone know where this bulb is located? Also, I need a driver's side headlight bezel, preferably NOS, and the cruise control solenoid, the one that controls vacuum to the servo. Any ideas on where to look, or does anyone here have any they are willing to sell? I've been checking ebay, and bought many parts there. Please reply to me at


04-18-05, 10:52 AM
Most of that fiber goes to either the headlamps or tail lamps I don't think there's a special bulb for that hidden somewhere.

Do all the headlight and tailight bulbs work? Side marker lights and all that jazz?

04-18-05, 09:20 PM
ok heres a even trickier question. i have a 79 coupe with a 78 door (previous owners did it, not me) that happens to have the same mirror. i didnt even know the thing lit up. so...im in the same position, minus knowing if theyre compatible. my right side marker is out and the thing that makes the interior light up on the drivers side, and the lil light under the handle dont work either. ill just hijack this thread, hehe

04-19-05, 10:25 AM
All of the other lights work, so I've no idea what else to do with it. Maybe someone on here does.

04-19-05, 11:04 AM
Have you checked the lights in the ashtray, behind the cruise switch, and behind the headlight switch?
There's more things that light up on my car... I didn't know I had about half a dozen bulbs burnt out on my '70 untill I took the dash apart looking for a solution to non-working taillights.

Of course, another possibility is that the optic fiber has gotten pulled out of wherever it is supposed to go.

04-19-05, 03:58 PM
Or if any of the lenses are cracked or ever have been the end of the fiber can get dirt on it. Remeber the glass itself is about 62 microns thick. Not very much area. Doesn't take much to block the light.