Does anyone have what they consider to be bright dash lights using standard incandescent bulbs?

I've removed the filters but the gauges are still dim. Having read essentially everything I can find regarding dash lights on the forum I haven't found a solution. But, I assume they were reasonably bright initially, so is it a problem with the rheostat not giving enough juice to the bulbs?

Similarly, I've read that some have gone to LED's but from what I read they've lost the ability to dim them - right? I understand why that would be since the LED's don't pull enough current to drop much voltage across the rheostat - although I think I see a solution to that.

Anyway, has anyone solved the problem of dimming the LED's?

 

Mine got significantly brighter after removing the filters, but still not what I would call "modern bright".

I replaced my headlight switch unit with a new motorcraft one and it did not brighten my instrument lights. But of course that doesn't prove your rheostat isn't worn/corroded/not conducting electricity as well as it should.

Its hard to compare what different people consider bright. There are plenty of pictures here to compare with though.

 

Poking the blue lenses out fixed mine good enough also. I suppose you could take a voltage reading on one of the blue/red wires and see what you really get. Maybe you need to do a "Brighter Lights Brighter Whites" relay modification to the cluster circuit

 

Yes, I had high hopes for my lights getting bright when I pulled the filters, but it only helped and didn't make them "bright". However, I do agree that might "bright" might be different than someone else's, especially since I'm 65 and need more light to see well than younger people do. As for the pictures, I could easily make mine look bright in a picture as I can tell the camera to stay open until it gets all the light it wants, so I'm skeptical of pictures.

But, if your new switch didn't fix it then that probably means mine isn't bad. Usually the brightest position is full battery voltage, so I'll check that out and see what mine is giving the bulbs.

Didn't see your post when I responded to Matt. Yes, I'll take that voltage reading. But, while I could do the relay what I was actually thinking of was to use the rheostat to control a voltage regulator that feeds LED's.

 

You could put a relay on the wire feeding the switch, and that would send full battery power to the switch and everything connected to it. I'd put the relay as close to the switch as possible so you have a very short run of wire from the relay to the switch. You could retain the dimming feature this way too.

I would also look at maybe running a new ground for the cluster straight to the battery, or perhaps tie into the bolt for the engine-to-firewall ground, so you'd have full power in and full power out.


As far as me, I removed the filters and put red 194s (and a few 168s in the center, slightly brighter than 194s) and it lights up nicely. Makes the white letters and icons appear to glow as though they're backlit.

 

If you want brighter dash lighting try #3652 bulbs in place of the #194 bulbs. The #3652 bulbs are rated at 75 lumens and the #194 bulbs are rated at 25 lumens. But, be careful because the #3652 runs hotter and may melt the plastic housing surrounding. I'm going to try them as soon as I get some time and warmer weather.

Another way to go is with L.E.D. lights made to replace the #194's. but, be careful of them because some of them won't fit into tight spaces because the housing that holds the L.E.D's. may be larger than the glass bulb of the #194.

I've been kicking brighter dash lighting around for a while and I may just go for the white gauge facings on ebay.

 

Gary, I replaced all the bulbs (white 194's) when I removed the covers.
With the rheostat on 'high', I wouldn't want them any brighter for night driving.
Sometime I might try blue lens bulbs for the original look.

 

I'm going to test the voltage today and report back, but I really doubt that we are losing enough juice to make those bulbs dim.

And, the fact that you used new bulbs, inc some 168's, and got "nice" lighting probably supports that theory. That's good to know and might be an easy solution.

Surely these things weren't as dim as they seem to be now when they were new. So I wouldn't think the white faces would be necessary, although they might be a nice upgrade even w/o the amount of light they would reflect being an issue.

That's the kind of thing that I'm looking for. That plus what Matt found seems to say that the biggest problem is the old bulbs, not low voltage or bad connections.

Ok guys, more later after I do some testing...........

 

The white replacement facings that I've seen give a soft but easy to see look with the regular #194 bulbs not turned up to full brightness. I suspect if you went with the white facings and brighter bulb you would be correct in thinking it would be too bright.

One other thing the white facings do is allow you to use colored bulbs to give a nice ,color of choice, glow to the gauges. The only reason I hesitate to go with the white gauge facings is I want to keep my truck as original as possible. For me, it's a tossup between originality and my old eyes seeing the dash gauges easier.

 

Old eyes? I could call myself old348, and they came out ~3 years ahead of the 409? (I know the 348 was in the 57 GMC pickup and the 409 didn't show until 60 - right?)

Yes, my 65 year old eyes aren't what they used to be and I need more light for most things, including gauges. But I, too, want to retain some of the originality so hesitate to go to white faced-gauges.

 

I found the regular white 194's to be too yellowish once the clouded blue filters had been removed. So I used blue glass 194's. I have not tried the 168 bulbs, but I remember they looked exactly the same size to me at the store.

 

I expieramented with the white face guages. Even with the blue filters I still have to turn the brightness down. Seein how you wanna keep it original id start with the 168 bulbs.

 

Just a word of advice, the Instrument lighting should be just as bright as the radio dial illumination and heater control panel.

If all three are dim, then something is wrong with the grounds or the rheostat on the light switch.

The ground behind the dash to the right of the radio or the firewall to engine ground etc...

If the instrument cluster is dimmer than the radio or heater panel, then it could be the printed circut needs cleaning, the blue/green pass filters are deteriorated and cloudly, or bad connections with the lamp sockets themselves.

Mine the blue/green filters were badly deteriorated.

I removed the filters and replaced the bulbs with GE: 194-G Green bulbs, (15+ years ago) and the color matches exactly to the original OEM color. It's just as bright as the radio as well, now.

Red, Green and Blue are the primary colors for mixing light. The same as your television set. RGB etc... The filters on the cluster blocks red light, and alows blue and green light to pass through. This is what gives the color we are familiar with, but it also blocks 1/3 of the light, even when the truck was new. When the filters deteriorate and become cloudy, it starts blocking even the blue and green light from passing.

This is also why if you paint your gauge needles RED, or ORANGE, and it's not a flourecent color, the needles will turn black with the stock light. No red light passes the filters to reflect the light of the needles back to your eye.

Also why removing the filters automaticly makes the cluster brighter. At least 1/3 brighter than stock.

 

Ok, a bit of info. I ran some tests, all of which were with all the dash lights on full, meaning that the switch for full illumination was on. However, while I made sure all the cluster lamps were on I don't have an ash tray lamp, my radio and HVAC control lamps are out, but I have two small lamps for the aftermarket gauges. So the voltage drop would be greater if I had all the lamps lit.

And, the tests were run by measuring between the battery's positive post for F1 and the cluster's light input, and from the battery's negative post for the check at the cluster's negative output.

Results:

• The voltage was 1.5 volts below that of the battery at Fuse 1, which is after the headlamp switch, for the original headlight switch.
• The voltage was 1.1 volt below that of the battery at F1 with a spare headlight switch I have - after I cleaned the rheostat with tuner cleaner.
• The voltage was 1.8 volts below battery voltage at the input connector to the gauge cluster with the original switch, but wasn't measured with the replacement switch.
• The ground for the instrument cluster was .04 volt above battery ground.
• If you don't seriously need to take your headlight switch out DON'T! It is a bear.

So, the grounds aren't the problem. But, there is a fair amount of drop between the battery and the fuse panel, and all that's there is a fusible link, some wire, several connectors, and the switch. Yes, we could put a relay in like for the headlights, but I'm thinking going with LED's would be a better approach as they don't pull enough juice to cause much voltage drop across the wiring. However, maybe I should try new bulbs first.

And, for future reference the rheostat is ~8 ohms. So, it wouldn't be difficult to make a voltage divider to use as input to a regulator to allow dimming the LED's. However, with that low of resistance we'd only have a limited range of output voltage for them w/o pulling lots of current. Gotta think about that more.........

 

Hmmm. It has occurred to me that a regulator isn't going to solve anything as its output will always be less than battery voltage. And, the way the rheostat is made there's little, if any, way to separate the switch from the coil, so I don't see a way to use the coil to adjust voltage and then override the regulator's output with the switch.

And, similarly, the relay idea is an all-or-nothing one since there seems to be no way to use the switch separate from the rheostat. So, when some voltage hits the relay's coil, regardless of how much, it'll pull in and give battery voltage to the lights. Well, battery voltage less the drop across across whatever fuse we use and the wires and connections.

Anyone have a better idea? What did I miss?