The Stovebolt Site Forums The Shop Area The Electrical Bay Instrument Panel Lights Not Working

Since I have the radio panel and speedo out of the truck, it gives me a little easier access to everything else under there.

The high beam indicator light is the only dash light that functions. None of the other gauge lights come on when the headlights are turned on.

I verified that all the bulbs work by putting them in the high beam socket.

I haven't begun to troubleshoot this at all but figured I'd ask what the most likely place is to look first.

I rewired the headlights a few years ago from the dimmer switch to the headlights themselves and all that works perfectly. Wiring under the dash is in generally good condition. Since all of the lights do not work, it seems logical that the problem lies at some point that they all share.

Headlight switch? Is there a junction somewhere that ties them all together?

Otto, The dash lights are usually all tied together to one wire going to headlight switch. The fact they are ALL out tells us that. They will either by splice, junction block or by previous owner method. Just follow them to discover. BE SURE YOU DON"T have the dimming knob turned all the way to off.
At the same time find the terminal on the headlight switch that is for dash and see that is is hot when dash lights are activated, knob rotated, whatever. You can also follow that wire from that end to discover how they are all tied.

The chance are the H/L wire end is off or you don't have the dash metal grounded good enought or you don't have any ground becase the dash is loose while you are working on it. Each bulb socket needs to have good ground contact in the hole.

You can tap a hot jumper on the H/L end to see if bulbs light. This will confirm wiring continuity and will confirm ground.

What Bartamos said about them all being tied to the same wire that's connected to the output terminal on the dimming knob on the headlight switch. Mine don't work either, and my original switch had an issue with the dimming rheostat that made that terminal dead. I happened to have a 12V headlight switch of the same style and figured I could use it by swapping the 6V circuit breaker over to it. But that didn't work out as the rheostat on the 12V switch had higher resistance, so the dash bulbs didn't work no matter what position the dimmer was in. Turns out that headlight switch has some other issues as well, so my plan is to replace the whole thing.
My bet is that your dimming rheostat has an issue causing the instrument lighting terminal to be dead. I'd pull the switch out and bench test it. You can confirm the wires to the bulbs is OK by connecting them to the headlight output terminal. They should come on at full brightness whenever the headlights are on assuming the wiring is OK.

If all else fails, attach dash light wire to tail light terminal.

I think he has a ground at the instrument panel, otherwise the high beam indicator would not light?

2nd Kevin’s light switch rheostat the spring in the porcelain can get corroded .There is a good tip on repairing the light switch by Jon G.

Thanks. I didn't even know the dash lights had a dimmer function. Which way is bright?

If that's the problem, I'll do what bartomos said and wire them to the taillight terminal. I want them full bright all the time so that would be perfect.

turn headlamp knob full clockwise it should click into the dome light then turn back 1/8 turn or so dome light switch is off that should be full bright.

Not sure about Otto's truck, but the only way to turn on the dome light on my '52 is use the switch on the lamp.

Ok. I didn't know the dome light had any other way to turn it on other than the switch on the bezel.

The dome light only has the switch on the bezel. The wire to the dome lamp is hot all the time.

Same with the '57, dome light is only by rotating the dimmer switch.

I would replace the headlight switch. I was having the same issue on my "58, the rheostat was severely corroded and not allowing any current flow. The high beam indicator is on a completely separate circuit than the dash and dome lights.

Thats what I would do. After getting a can of Deoxit and cleaning the contacts/ on the switch.
Does the switch have a fuse?
Those are pretty tough switches. I have 2 old ones that sure don`t look like they would work but do.

I did determine that the dash lights are not turned all the way down so it probably is the rheostat. I'd like to take the suggestion to connect them to the taillight terminal.

I'm trying to orient my switch with the diagram in the manual but I'm not sure what's what.

Can any of you tell me which terminals on this switch should be taillight and dash light?

It's a pretty crummy pic so I can squeeze under there and try to get a better one if necessary.

Otto, From the 1948-51 Chevrolet Shop manual.

Yes, I have that diagram but I can't reconcile it with the actual switch. Which way is it oriented in the dash>

Otto,
Per the drawing pic that both you and Dan provided, the switch in your pic is flipped 180 degrees. Per Dan's drawing the terminal with 3 screws for ammeter are on the left. Per your pics the terminal is on the right and with two screws missing. The terminalin question for instrumentation and ignition lock light is out of sight in your pic (somewhere lower left of your pic).

IIRC, The switch is oriented in the dash the same way as shown in the manual. The 3 central connections (parking lights/tail lights/dimmer switch) pointing down towards the floor board and the 2 side by side central connections (stop light switch and dome lamp) pointing up to the top of dash. The view pictured is looking from the drivers side to passenger side with the knob towards the cab compartment/seat.

Thanks Craig and Dan. That helps me understand what I'm looking at.

To get it straight in my head, the single wire attached to the terminal at the right end of my switch (above the two missing terminals) is actually the "bottom" terminal in Dan's FSM illustration. Correct?

The taillight terminal in my photo is the center one to the right of the wire with the black sleeve on it which corresponds to the center of the three terminals on the "bottom" of the switch diagram. Correct?

This would mean that the instrument panel light terminal would be the first one from the dash on the "bottom" of my switch. Not visible in photo, I think.

Does this sound right?

Does this mean that my switch is/was installed upside down relative to the shop manual illustration? Does it matter?

Otto, this pic may help. Here's Dan's photo marked in red on the bus bar from the tail light terminal to the instrument light rheostat. The furthest forward (right) on your photo is power coming in from the Ammeter, the next one is Park Lights, the center is Tail Lights, and the next is Headlights (via the dimmer switch).

I'm not seeing the bus bar on your switch photo going to the instrument light rheostat that I highlighted in red. If that's missing, there won't be any power going to the rheostat, and of course nothing coming out of it to the instrument lights. If that has broken off it would explain why your instrument panel lights don't work. If you connect the wire going to them to the Park Light terminal, they'll be on full brightness anytime you pull the light switch out one notch.

Kevin/Otto, my suggestion is to forget dimming. It is not necessary. Just attach the dash lights daisy line directly to the tail light terminal.

Not my decision, Ken, but that's a possibility to get some light on the instrument panel.

Otto, just attach the line comming from all the dash lights to the tail light terminal on the headlight switch seen on Gdads51 original pic.

LOL! I think this horse is officially dead. Otto said he was going to do that 19 posts ago.

Yes the horse is dead

That's right. I've never dimmed the instrument panel on any vehicle I've ever owned. I like full brightness all the time so moving that connection to the taillight terminal is going to be the plan.

Some think electrons flow better downhill.

victim=50 4400
more dog food.
fyi just a hour ago i removed the knob with stem and shot some wd40 into the switch, replaced stem and wa-la the dash lights came on.
i did this 8 years ago on my 48 survivor 3609 platform bed to get its dash lights working too.
good luck.

Otto I had the same problem when I rewired my 54 3100.. I then linked all the lights ground to the cluster attach bolts and daisy chained them all to a ground on the frame.. everything worked after that..

Doug

I just finished hooking up the gauge lights to the taillight terminal and for the first time I can see the instruments at night. Thanks for the help. If I can get my phone and computer to start talking to each other again, I'll post a photo.

Woohoo! Lighted gauges!

Camera angle makes them look wonky.

Looks great.
Did you also do the ignition/key light?

I had one bulb that was burnt out so I left it out of the ignition socket. I tested it and it works. I'll just replace the bulb in the future.