Dim dash lights

[tdyltc46]

Hi Guys

The dash lights on my 66 Mustang convertible are next to nonexistant. There is light behind each gauge but it very dim even on the highest dimmer setting. Does anybody have any suggestions as to what would cause this?

 

[krash kendall]

Headlight switch may be faulty or a bad ground in your dash cluster. The screws that go through the plastic bezel have to have good contact with both the steel structural dash and the retainer/guides providing conductivity between the mostly plastic cluster and the ground structure.

 

[tx65coupe]

It could just be that some bulbs are burned out as well.

 

[chris66dad]

I replaced my bulbs on the 66 with 5x LED light bulbs. I also removed the plastic lens caps that had become dark and bubbled from the light bulbs heat.
The LED bulbs made a huge difference.
Here is the vendor and pictures of what to expect with the change out:
http://cgi.ebay.com/ebaymotors/1965...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

Good Luck and Be Safe
Ron

 

[tdyltc46]

Thanks for the help guys. I am going to look into the LED swap but in the meantime I am thinking bad ground or switch. I am pretty sure all the bulbs work. I have had the dash cluster out several times over the years. Isn't there some kind of small dash light voltage regulator back there? Could that be faulty?

 

[chris66dad]

The voltage regulator (next to bottom of the speedometer cable input) is only used for the gauges.
Does the dimmer on the light switch work? Is it fully on?
My sockets were corroded and a little sandpaper cleaned up the contacts.
The ground for the cluster comes off of the Black wire above the instrument voltage regulator and it runs to the firewall behind the cluster hole on the right side. This is the ground for the dash lights also.
Here is a diagram:
http://hammar.dyndns.org/~djhamma/wiring/1966/66instr.jpg

Good Luck and BE Safe
Ron

 

[tdyltc46]

Thanks again for the informative reply. Yes, the dimmer switch has an affect on the brightness but, as I said in my opening post, even at its best it is barely visible.

 

[zigmont]

I tried some LED's, in my 65 but they werent bright enough. So I removed the blue filters from the cluster, and replaced all of the bulbs. Without the filters there is enough light now. AND I can adjust the brightness with my light switch. Also, when you use LED's you get what you get. There is no longer any brightness adjustment. Since they use so little current, the rheostat in the light switch has little effect on them.
Just my $.02

 

[2+2GT]

It's easy to test the idea that the headlight switch or ground may be at fault. Connect a test jumper to the housing and ground it. Better? OK, now connect another jumper to a 12V source and the + of the lamps on the housing. Better now? If neither of these makes it brighter, check the blue filters for dirt and discoloration. They are available new. The white inside the housing can get dirty, too, don't ask me how.

One thing to remember, though, is back then the idea was to adjust the lights to the same brightness as the road surface ahead of you. Today's cars have lights way brighter than that, I've never turned the lights of my late-model car more than halfway up, they have enough power to kill my night vision!

 

[tdyltc46]

You guys have all been very helpful. I am going to do the tests that 2+2GT suggested. Even though I am pretty sure all of the bulbs work, If I am going to have the dash cluster out, I might as well replace the old bulbs. When you removed the old filters, did it change the color of the gauge lights?

 

[2+2GT]

Without the filters, the lights are white, uneven and uncomfortably bright. Oddly, you can get other colors, such as amber.

 

[chris66dad]

The original LED bulbs that were on the market were only 2x. The new 5x bulbs are twice as bright as the the 2x LED and 4 times brighter than the original bulbs.
If you remove the filters the light will be white.
If you are taking the cluster apart to change bulbs, be sure to get some paint and touch up your needles. It freshens up the cluster nicely

Good Luck and BE Safe
Ron

 

[tdyltc46]

Thanks for the tip regarding touching up the needles; I would have never thought to do that.

 

[65ShelbyClone]

Has anyone tried installing wide angle/high intensity LEDs into the original bulb bases? I have done it with flashlights and it's not hard to fit a 1/4 watt resistor under the LED once the glass and glue is broken out. I was thinking about trying it with my '68.

 

[2+2GT]

Thanks for the tip regarding touching up the needles; I would have never thought to do that.

Careful- I got a bottle from Glazier's, and the instrument needles looked so much better I had to take the friggin' Rally Pac and radio apart and paint them, too.