Dash Bulb Change to 12V

[truk4u]

Well, I did it. Changed out all the rockers and instruments to 12V, set the rheostat (dimmer) to 12V and wow what a difference. I took some pic's, but it didn't do it justice. Total Cost - 21.00 and about 2 hours work. All bulbs in the Prevost Parts Book have a 12 and 24 volt version, so they must have went both ways at one time. All the warning lights are still 24V and seem bright enough.

Rocker Mini Bulbs - Prevost - 12V - New Part 10507852 - Increased Wattage
Dash Lights - Auto Parts Store - 12V - 1893 or similar

I took Peters advise and marked the dimmer switch so I know exactly where the 12V settings is. If I turn it to 14V, I need sunglasses.:D

[jello_jeep]

Good thinking! It is on my long list to look at, along with a million others :)

[bill&jody]

dr. tom-
where'd you get the parts - my rheostat is hosed, needs replacement.

wmm

[rfoster]

Tom: Good for you! I have needed a fix for that problem for some time now. I recommend they double your pay for this progressive move. I'll speak to Jon personally on your behalf about this achievement. When the rest of these old fart bus owners drive at night they too will realize how poorly the Prevost Factory Dash Lights are!:cool:

[MangoMike]

Tom,
I hope you win the coveted A1 award for this suggestion. It may be the cynic in me, but I'm going to wait until POG III to see if yours are still shining. ;)

Mike

[truk4u]

C'mon Jon, open up the dash and check a bulb to see if your dimmer will adjust down to 12V.:rolleyes: If so, this will work for most, but if I have a whimpy dimmer, others may not get the same result.

Bill - I think any dimmer will work, the part number on mine is 562489.

Mango - You have doubts?:eek:

King - Now Harry and Lew may be able to drive at night:p

[Jon Wehrenberg]

Tom,

I can do exactly what you suggest, but I have two gauges that were Liberty installed and they are not on the dimmer circuit, and the varying intensity of the lighting on the gauges now is such that if I am able to get the speedometer intensity up slightly above the black hole level it is now, the rest of my lights will look like LEDs on steroids.

BTW, none of the warning lights are on the dimmer and that is another sore point with my tired old eyes. I have a few that are so dim I can only see them if I park the bus in a dark garage during a total eclipse of the moon on an overcast night, and a few that are so bright I think they were formally used for runway approach lights.

[truk4u]

Thanks Jon, my warning lights aren't quite as bad as yours, but if there is any sunlight, I can't even see the turn signal indicators. Hopefully if one of the really bad warning lights come on, I'll see it. The stop engine, warning and turns are 12V, so maybe a brighter bulb is available for those. My next project will see if there are bulbs to replace the 24V warning lights with just a little more wattage.;)

[Jon Wehrenberg]

Tom,

I cannot remember a lot of the particulars, but on my 1987 the annunciator lights were different than the ones on my 97.

For example, now I have some I did not have previously, such as an indicator when the refrigerator is powered up (I don't know why this is important, but it is there), but I lack some such as an annunciator light when the cruise control is engaged. I did not have a light to indicate braking previously, but i do now.

The lights that were on back then, or which came on frequently were too bright at night, so Prevost changed the bulb wattage. Those lights that you really needed to see such as low coolant were bright in daylight or at night, but others such as the cruise control light had their wattage reduced substantially. The net result was those lights were hard to see in daylight, and easily got washed out by the sun, but at night they were not going to blind you.

If you want the A1 award, you have to do it right.

Add a photocell to the warning light circuits, and during periods of light allow the bulbs to operate at maximum intensity, but at night change the resistance in the bulb circuits so the intensity is still sufficient but not so intense a light like the braking light blinds you.

In essence I am asking you to do what the engineers should have done from the beginning, especially considering the few bucks of cost are negligible on a vehicle that cost as much as these shells cost when new. How tough can it be to balance the dash lighting? Apparently tougher than we think.