Dash Light Bulbs

[truk4u]

OK boys, here's one for ya! I have some bulbs out in the dash gauges and the bulbs are number 1820. This bulb according to Bulbs.com are 28V. I have replacement bulbs in stock, 1893 that are 14V. I'll be referring to these bulbs as 12 or 24 volt.

Here's the deal... When measuring voltage at all the lights using the rheostat, the voltage ranges from 10V to 18V. The dash lights working are rather dim. So, if the rheostat can control the voltage at 12V, I should be able to use the 12V bulbs. At the 12V setting using the 12V bulbs, the gauges are much brighter than the 24V bulbs at 18V.

Or is my rheostat going south? :confused:

[JIM CHALOUPKA]

OK Tom, The way I see the situation is whoever installed the 28v and 14v lamps did so to have them over rated for longevity of operation. That is a filament that could withstand a higher voltage working at a reduced voltage will last longer because it is heavier, but it will not give off as much light as when it is getting its design voltage. I do not think anything is wrong with your reostat. You state at the 12v setting using the 12v lamp the light illuminates the way you expect it to and that is because it is opperating at it's design voltage. You further say the 24v bulbs are dimmer at 18v than at 24v, this is because they are 6v under their design voltage. To prove the point put the 14v bulbs in the 24v positions and they will we very bright for a very short time. JIM

[MangoMike]

I wonder why you're not getting 24v at the bulbs?

mm

[JIM CHALOUPKA]

Tom, I didn't take it Mango's way. He has a point. If all you are able to get from the stat is 18v then it is probably heading south before you. JIM :D

[lewpopp]

I expect you guys are speaking of the lights in the guages and not the push button switches. Clarify that please for I have bulbs for the push button light switches.

I don't drive at night or haven't for a long time so I maybe I should check them out in case I have to.

Lew

[truk4u]

Thanks guys... Any chance someone could put a meter on one of your bulb sockets and see what you have for voltage using the rheostat? If the rheostat is suppose to put out a full 24V, I would like to know before replacing. Otherwise, I'm going to change to 12V bulbs and set the rheostat to 12V. At that setting, they are nice and bright like they should be. Mine is a 96 chassis.

Lew - The rheostat controls the briteness of rocker light switches as well as the gauges.

[truk4u]

Not a high profile job, but eventually you'll have to replace those small lights inside your dash rocker switches. Here's the HOW TO:

Mango,
This was your how to back in Nov on the rocker bulbs. Did you find they were 12 or 24? Those little bulbs are just for the night lighting (rheostat) and the actual switch light that comes on when you depress the rocker must be internal and part of the switch.

This is a nightmare... Could the rockers be 12 and the dash 24? If so, the rheostat would burn out the 12 at a high setting.

Are you all confused yet?:confused:

[Joe Cannarozzi]

Did somebody say Stewart-Warner

[MangoMike]

Tom,

Honestly I don't know/remember. I'll check the invoice to see what I actually bought. However I do know that there's only one bulb in those rocker switches and they are controlled by the rheostat. I don't recall them blinking on when pressed.

http://www.prevoman.com/Pages/Dash%20Light/IMG_3202.jpg

Mike

Truk if you do solve the dim lighting problem on the dash you'll be raised up to A1 status.

[Jon Wehrenberg]

I have solved the dash lighting problem on my coach and will post pictures this afternoon.

Nobody takes away my A1 status, although Tom can borrow it.

[truk4u]

I'll borrow the A1, I'm not resting until I get the dead bulbs fixed!:mad:

More bulb crap for the experts... This is the tach bulb, not to be found anywhere in the internet universe. Number is OSRAM24V3WW5P. Note the little slides on the side instead of the usual little tit. No offense girls....

599

[Joe Cannarozzi]

That is just like the bulb for the analog dash clock in the Pete that is unlike any of the other bulbs.

[Jon Wehrenberg]

Problems relating to dash and instrument lighting are not new. On my 1987 the instuments ate light bulbs. Every few months I was taking the instrument panel out and replacing bulbs.

Even when all the bulbs were functioning the lighting was poor. Some instruments looked like they were lit with a halogen headlamp and others were so dim they could hardly be seen. Then there were the switch lights. They also varied in intensity, and some of them had lights with the lifespan of a gnat.

In the ten years between coaches nothing has changed. The lighting on the 97 I now have varies in intensity, and my speedometer is all but invisible. That is offset by the converter installed volt/ammeters for the house and bus. The switch lights were at least half out when we got the bus in Aug. of 2004 and they are starting to fail again. The worst part it I don't like to drive at night, so the bulbs do not have many hours on them when they fail.

So I borrowed an idea from my plane. I have a map light that I can use to bathe my entire instument panel in the plane in red light. Our coach has two red lensed map lights and the one on my side helps tremendously for instrument panel visibility in the dark. The only problem is it is mounted in the wrong spot so I located a source for the same light and added a second map light to my side of the coach.

The new one was added above the instrument panel in such a way that it would bathe the entire panel in an even red light, but would not cast any shadows, and would not put any glare on the windshield or anywhere that would impact my ability to see the road.

I chose the Hella HL62643 reading lamp from Susquehanna Motor Sports at www.rallylights.com but you can use a light with a flex arm or any map light with a red lens to eliminate the need for any instrument lights other than that light.

[truk4u]

Jon - Good idea, that takes care of all the lighting issues...

Mango - The little bulbs on mine for the rocker switches are 24V, Prevost #561123, Vendor #78271, Part #2741. Also, I'll clarify my rambling about the internal switch light. Some of the rockers have an internal light that glows when the switch is depressed, such as the mirror heat and stays on as long as the switch is in the on position. That internal light is seperate from the little illumination bulb that your post referred to that's controlled by the dimmer with all the other dash lights. I believe that you have to replace the entire switch if that internal light doesn't work.

Here's a quick summary of bulbs for my vintage Marathon per the book...

Exterior Lights (except compartments) - 12V
Compartment - 24V
All interior lights (except Check Engine, Stop Engine and Flasher) - 24V
Check Engine, Stop Engine & Flasher - 12V

[MangoMike]

Jon,

With all due respect that's a perfect solution IF YOU'RE FLYING A CESSNA! Truk4mebaby you still can win the coveted A1 if you solve the dim dash light problem.

The mini bulb Prevost sent me were #562336 24v (1.2watt) which looks like were a replacement for 561123.

Bulbs for the speedo and tach were # 560145 24v (also listed as 1829).

I stand corrected on the 2nd mini light.

mm

[Just Plain Jeff]

I had every confidence you guys could figure out the dash lights...but the consequences....whew....




http://static.flickr.com/23/34708967_55ac921e35_b.jpg

[Joe Cannarozzi]

Tom
Did you ever find that bulb with the odd tabs? I ment to take the one out of my clock in the truck and take a pic. but forgot. Im sure its the same bulb though.

[truk4u]

Joe,

Thanks for the offer, but I ordered two of them with my fingers crossed. The part number appears to be 382, that's the 12V version. I decided to change out all rocker and dash bulbs for 12V and set the dimmer as I mentioned for 12V. I'll let you know how it all comes out. So far, the gauge lights are great.

[blacklab]

I would like to know if the "green" lense on the rocker switch is from Prevost or not. I ordered one from recently and it came W/O the green lense.

[Petervs]

Joe,

Thanks for the offer, but I ordered two of them with my fingers crossed. The part number appears to be 382, that's the 12V version. I decided to change out all rocker and dash bulbs for 12V and set the dimmer as I mentioned for 12V. I'll let you know how it all comes out. So far, the gauge lights are great.


I think this is a great idea, but you will want to pin or lock the rheostat so you can not turn it past the 12 or 13 volt point accidentally. If you like the results, please advise, I will do the same I think.

PetervS

[Jon Wehrenberg]

I think Tom's idea makes sense, and Peter has a very good suggestion, but how do you deal with instruments that have varying degrees of intensity. When my instruments are brightly lit, my speedometer is a black hole that requires Braille for reading.

[win42]

Dale J: I think it's time to help these poor souls out by telling them about LED bulbs for their instrument lighting. Let us know what you come up with.