1938 Instrument Panel Lights

[EmTee]

Sad to say, but days are getting shorter here up North...  As a result, I have actually needed to use my headlights on the way home from cruise-ins a couple of times over the last two weeks.  Good news is the headlights work fine, but I had no dash lights.  So, reading the Owner's Manual I discovered there's a separate switch to turn the instrument lights on.  The same switch controls the map light (another not-so burning question I had).  Oh -- and the switch is hidden on the underside of the dash between the parking brake handle and the steering column!  The only less ergonomic control would be the trip odometer reset knob...

 

My question: Why did Buick make control of the instrument lights a separate switch instead of slaving them to the exterior lights, as in more modern cars?  When would someone have the headlights on and not want the instrument panel illuminated?  Seems counterintuitive to me... 

[MCHinson]

I don't have any idea why they did it that way, but they did. Perhaps they were thinking that a driver would want to be able to switch between the instrument lights and map light, and never thought about just having a single off/on switch for the map light separate from the instrument lights. It would be interesting to find out what year Buick went to dash lights on the headlight circuit. 

 

Now that you are using the instrument lights, be very careful to turn them off when you park the car in the garage. When you park in a lighted garage, you can't really see the instrument panel lights and if you forget to turn them off, and then don't drive the car for a few days, you could end up with a dead battery. I had a similar thing happen once when my wife's elbow turned on the dome light accidentally when exiting my 1937 Century and I did not notice it in the lighted garage. Those little lights can eventually deplete a battery. 

[BuickTom87]

I guess buick wasn’t thinking that far ahead. I often wonder why they did certain things but maybe they had a reason but I guess we will never know. My 1938 was all re wired by the original owner but he never finished . So when we bought it, we ran into the same issue. So when we finished the wiring, we were scratching our heads because the instrument lights weren’t working. We never realized there was a switch for the instrument lights. 

[Daves1940Buick56S]

I think they were separate from Day 1. Still separate in 48. I think maybe 49 was the first year they were slaved but there is a separate control for dimming. My 38 had a slide switch, one side for map and the other way for panel. No dimming. I put in a switch that replaces that and allows for 2 brightness settings. I also have a separate swiotch for the map light in the center of the dash.

 

The switch for my 1940 is stock. Center, all off. To the left activates the map light above the ignition switch. To the right, 2 postions for panel lights, one bright and one dim. The 41  and onward has a switch on the center panel for instrument lights with 2 or 3 dimming positions, I can't remember.

[Bloo]

It was customary to run the dash lights really low so your eyes would stay adjusted to the dark. That's why old cars that don't have any adjustment for dash light brightness have really dim dash lights by default. I imagine some people turned them off entirely unless they wanted to have a look.

[neil morse]

I've heard that the reason is that they were concerned about the reflection of the dash lights off the windshield interfering with the driver's view of the road.   In another thread about this, I remember someone posting that their father said never use your dash lights at night unless absolutely necessary.   If you think about the way the flat windshield is angled back, this kind of makes sense.   On my '41 there's a separate switch, but the dash lights only turn on if the headlights or parking lights are on.   So as long as you turn your headlights off, you don't need to worry about the battery drain problem.

[neil morse]

Bloo and I posted at the same time.

[EmTee]

11 minutes ago, Daves1940Buick56S said:

I think they were separate from Day 1.

Yes, the schematic shows the separate switch for the map light and instrument lamps.  It's a two-position slide switch; one way for map light and the other way for instrument lights.  I considered running a jumper to the instrument lights from the parking light terminal on the headlight switch since they seem to be on whenever the headlights are on.  I decided, however, to leave it as Buick designed it for now so that I can appreciate the full 1938 driving experience! 

[Bloo]

The dash lights should come on in the map light position too I think.

 

[EmTee]

10 minutes ago, neil morse said:

I've heard that the reason is that they were concerned about the reflection of the dash lights off the windshield interfering with the driver's view of the road.

I can understand the concern - I'll have to see what happens next time I run the headlights and turn-on the instrument lights.  On a related subject, I can fully understand why designers moved away from using flat glass on instrument panels.  The daytime glare at times renders the gauges unreadable...

Edited August 21, 2022 by EmTee (see edit history)

[MCHinson]

1 minute ago, Bloo said:

The dash lights should come on in the map light position too I think.

 

They don't. The switch is Center off, Dash lights on one side and Map lights on the other side. That is how they are on 1937 and 1938 Buicks. Those are the only two years with which I have personal experience.

[Rock10]

I think our 36 was the same way, but when it was rewired in the past they moved the dash lights to the headlight switch.

[Bloo]

Are you sure the switch isn't there? Maybe it is just "on". It sticks straight down out of the bottom of the dash, slightly toward the driver from center.

[EmTee]

16 minutes ago, Bloo said:

Maybe it is just "on".

If it's like my '38, the lights are not fed from the ignition switch, as Matt Hinson noted above.  So, unless the hot feed was also changed, leaving the instrument lights on will eventually kill the battery...

 

Edited August 21, 2022 by EmTee (see edit history)

[DonMicheletti]

Having had the experience of leaving the very dim dash lights on and ending up with a dead battery, I wired the feed for the dash / map light to the tail light terminal on the headlight switch.  Just like a modern car.

I have never had a need to use the map light and the tail lights are on in all the headlight switch positions.

 

 

[Bloo]

Buick seriously had that wired so the dash lights stay on with the tail lights off? Wow. That's crazy. You would never see them.

[Buick35]

My 35 Buicks dash lights come on with the headlight switch, the dome light is on a separate switch.

[neil morse]

1 hour ago, Bloo said:

Buick seriously had that wired so the dash lights stay on with the tail lights off? Wow. That's crazy. You would never see them.

As noted, the problem was taken care of by '41 -- maybe earlier, I don't know.  On the '41, the dash light switch is wired through the headlight switch so it only has power when either the parking lights or headlights are on.  (The dash light switch has three different intensities -- with the original incandescent bulbs I would say they range from "barely visible" to "hardly visible" to "Hey, is this thing on?"  With LED bulbs, you lose the ability to vary the intensity, but they are quite bright.)  There is also a separate map light on the '41.  So maybe the problem in '38 was that they didn't want to pay for a separate circuit and switch for the map light.

[Bloo]

On my 36 Pontiac, there is a switch that looks and feels exactly like the 37 Buick one, and mounts in the same hole, although It is not quite the same switch. Maybe it was the number of terminals that was different. I remember finding only Buick switches when I was looking for one. Since I couldn't find a Pontiac one, I recall copying the knob on @37_Roadmaster_C's 1937 Buick 80C to replace the missing knob when I rebuilt the switch. Mine is left for dash lights, right for map and dash. I feel certain the dash lights go off with the headlight switch too, but now I will have to check to be sure. I have never had a dead battery (yet) for forgetting to turn the dash lights off.

 

[EmTee]

5 hours ago, DonMicheletti said:

Having had the experience of leaving the very dim dash lights on and ending up with a dead battery, I wired the feed for the dash / map light to the tail light terminal on the headlight switch.  Just like a modern car.

That was going to be my 'hack' also, but I've decided to try it "the Buick way" until I determine whether there's any advantage to having the dash lights off with the headlights on (or I kill the battery)...

[Bloo]

If I am understanding this correctly, if you do what @DonMicheletti is suggesting, you can still shut the dash lights off if you want, you just can't leave them on. I am going to check @37_Roadmaster_C 's 1937 80c the next time I see it and see if the change has been made. It sure sounds like a good idea to me.

 

Edited August 21, 2022 by Bloo (see edit history)

[Daves1940Buick56S]

When I had the dash out on my '38, I put in 6V bus bars fed by heavy relays with power directly from the live batt circuit and controlled by the ignition switch line. So when I turn off the ignition all goes off but the headlight/park/tail lights and brake light circuit. Edit: and the clock! Forgot about that!

Edited August 22, 2022 by Daves1940Buick56S (see edit history)

[EmTee]

32 minutes ago, Bloo said:

If I am understanding this correctly, if you do what @DonMicheletti is suggesting, you can still shut the dash lights off if you want, you just can't leave them on

I guess it depends on whether the dash light is fed directly from the headlight switch (bypassing the existing dash switch) or the power feed to the existing dash switch is moved to the tail light tap on the headlight switch.  I was thinking the former, which would slave the dash lights to the tail lights and render the existing switch only functional for the map light.  If the latter, then what @Bloo said would be true.  The existing switch could be left in the 'dash light' position and they'd come on with the headlights, but could be turned off using the existing switch.  The map light, however, would only function when the tail lights are on (probably OK).

[DonMicheletti]

Yes, you can shut them off. You just cant turn them on when the headlight switch is off.

The ignition switch would be a good feed too

[sloperlad]

Hi. 

I gave up on using the dash lights on the 38 sloper. Only had candle light turned down low. Could not see a thing at night. Took the cheap option and purchased a magnetic torch from a auto shop. Works brilliantly, shines light down and no window reflections.