LED Dash Bulbs

[SteveGoldfarb]

I recently purchased a couple of screw- =mount LED dash bulbs from Moss for my negative ground Bugeye. The previous conventional bulbs worked properly. The LED bulbs seemed to screw-in and seat properly, but when I turned my lights on they didn't work. I reinstalled them and cleaned the contacts, but still no go.
Ideas?

 

[BlueMax]

Recently was installing a new wiring harness last month. While installing the conventional bulb purchase from Moss that showed made in China bulb, would not screw in. At first, I look at the bulb holder thinking something was made incorrectly. Went to and tried bulb in the original harness with same result. I order genuine Lucas bulbs and installed without any issues, returning bulbs back to Moss with an explanation of not fitting.

 

[ShawnC_at_Moss]

Hi Steve,
This is a reply from our tech guy who handles electrical issues.

LED’s enjoy a stellar reputation, However, it would be wrong to say they never have issues. It’s rare, but it happens.
Our suggestion would be to take the bulbs and a pair of jumper leads, then go to your battery.
Use the battery to apply power to the LED’s.
If they light, the bulbs are fine.

If the bulbs are fine, the most common problem is a weak wire connection or ground issues with the sockets.

In case you want to know…
When electricity faces an obstacle, it tries to get through it. Electricity’s capacity to overcome obstacles is measured in voltage. (Your car battery has enough amperage to kill you. However, you can put your hands on the two terminals and nothing happens to you. The reason is voltage. 12 volts cannot overcome the resistance in your body. If you try the same test with a 120 volt wall outlet at home, you will get a different outcome.) The voltage needed to overcome a specific level of resistance is called break-down voltage. LED’s have very little voltage going through them. So, their ability to break through resistance is limited.
That’s why clean wire connections and clean sockets are so important.

Let me know if you have any other questions.

Shawn

 

[nomad]

LED stands for 'light emitting diode'. A diode only allows current to flow in one direction and I would be willing to bet that if you try the LED's with the polarity reversed to negative ground that they will light.

Kurt.

 

[Keoke]

LED’s enjoy a stellar reputation, However, it would be wrong to say they never have issues. It’s rare, but it happens.
Our suggestion would be to take the bulbs and a pair of jumper leads, then go to your battery.
Use the battery to apply power to the LED’s.
If they light, the bulbs are fine.

Provided you use the proper current limiting resistor otherwise you may blow the led.

However, I do not know what these responses have to do with mechanically ill fitting lamps?????

 

[MGNoir]

LED stands for 'light emitting diode'. A diode only allows current to flow in one direction and I would be willing to bet that if you try the LED's with the polarity reversed to negative ground that they will light.

Kurt.

You probably hit the nail on the head there, and it may be a really simple issue. Moss sells both negative and positive ground versions - did you just get the wrong ones? I'm assuming the difference is a switched polarity in the base. And an LED put in "backwards" just does nothing.

 

[dklawson]

There have been many valid points above.

The items in question are not discrete LEDs, these are lamp assemblies with screw bases. While the bases may have manufacturing issues (yet to be proven) the LED lamps already include the necessary dropping resistors to operate in our 12V cars. Yes, Moss offers positive and negative ground versions of these lamps

That limits the possibilities here to:
1) Positive ground bulbs bought/supplied for a negative ground car (Post #1 says negative ground car)
2) A manufacturing problem with the base of the lamps preventing good contact (Suggested as possible in post #2)
3) Defective lamps. (Test method suggested in Post #3)

Post #3 from Shawn at Moss explains how to bench test the bulbs. What he did not mention is whether these bulbs also include reverse polarity protection (it is not mentioned on the web site either). What happens if you hook up the wires wrong when bench testing these lamps? A best case scenario would be no damage, reverse the wires. A worst case would be letting the white smoke out.

I am curious to know if Steve has had the opportunity to bench test the problem bulbs.

For reference, the Moss screw-base dash/gauge lamp #s are below.
171-000 Incandescent
170-970 Negative Ground
170-975 Positive Ground

 

[recordsj]

There have been many valid points above.

The items in question are not discrete LEDs, these are lamp assemblies with screw bases. While the bases may have manufacturing issues (yet to be proven) the LED lamps already include the necessary dropping resistors to operate in our 12V cars. Yes, Moss offers positive and negative ground versions of these lamps

That limits the possibilities here to:
1) Positive ground bulbs bought/supplied for a negative ground car (Post #1 says negative ground car)
2) A manufacturing problem with the base of the lamps preventing good contact (Suggested as possible in post #2)
3) Defective lamps. (Test method suggested in Post #3)

Post #3 from Shawn at Moss explains how to bench test the bulbs. What he did not mention is whether these bulbs also include reverse polarity protection (it is not mentioned on the web site either). What happens if you hook up the wires wrong when bench testing these lamps? A best case scenario would be no damage, reverse the wires. A worst case would be letting the white smoke out.

I am curious to know if Steve has had the opportunity to bench test the problem bulbs.

For reference, the Moss screw-base dash/gauge lamp #s are below.
171-000 Incandescent
170-970 Negative Ground
170-975 Positive Ground

Great engineering analysis Doug!
I second your comments.

 

[Keoke]

HI DK
Others are havivgdifferent results:

I originally used Superbright LEDs along with the FL-3 flasher. The initial set up failed. Then bought non-polarized LEDs. That didn't work either. Got the flashers to work, but the instrument panel flasher blub blinked like crazy. Also, sometimes I had no rear light or front light. I worked on this project for over 6 months. Trying different types of flasher units. The FL-3 would not work for me. At the same time I was replacing all instrument panel bulbs with LEDs. In frustration I located a manufacturer in Oregon. Classic Auto LEDs, LLC. Steve was my saving grace. I bought his products; personally talked to him on several occasions. Finally - everything worked to include all the dash LEDs. The correct Load Resistor is a RL-650 6 ohm 50 watt. As for the flasher, Negative ground cars can use an electronic or electromechanical flasher. Positive ground cars MUST used an electromechanical flasher. Electromechanical Flasher : Tridon EL12 (2 pin) or Tridon EL13 (3 pin). Electronic Flasher : CEC Industries EF32 or EF33 OR Bussmann 232 or 233. I bought the Tridon EL13 at Auto Zone. I have 2 sets of Amber and Red non-polar & polar leds; 2 load resistors; and 1 FL-3 flasher now in the parts bin. Hope this helps... Mert​

 

[dklawson]

Keoke, I have no comments or suggestions as your post above is focused on LED turn signals lamps.

The OP is dealing with screw-in bulbs purchased for his instruments and dash and that is what my comments were specifically focused towards.

 

[SteveGoldfarb]

Thanks for the advice...after some fiddling with the contacts they finally worked. Make quite a difference.