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?

[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

[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?

[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.



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.