Indicator switch light - Bad behavior

[Benny]

Before installing my Mk.1 indicator switch, I tested the light by connecting it to the leads of a 6V battery charger. I connected the positive clip to the light green wire, and the negative clip to the body of the switch, and the light came on, bright and steady.

When I installed it on the column, I get one feeble flicker out of the light as the switch is first flipped, and then nothing more. I checked the voltage at the terminals on the switch that feed the bulb, and I'm getting a steady, 5-6V pulse to those terminals when the indicators are switched on, so I have power.

It seems to me that this is consistent with a bad ground, correct? However, no matter what I do, I can't change this behavior. I've even tried clipping a separate ground to the switch body, but it makes absolutely no difference. I spent about 30 minutes trying to establish a good ground, and I couldn't change this issue one bit.

Has anyone struggled with this before?

[BRI MK1]

Check flasher can this can cause this sort of problem.

[Benny]

Flasher is brand new one provided by MiniSpares, and is providing voltage pulse. What should I be checking for?

[slowboy]

I would suggest to check for a broken or partly broken wire down the indicator stalk,

[minimans]

Check the bulb, make sure it's tight in the holder. make sure the path to ground is good at attachment point to column.

[Keith Grendahl]

Mine would do that if it is not used regularly. After dissembling and cleaning/shining all contact areas it works flawlessly.

[Benny]

After spending way too many hours on this, I may have stumbled onto something. I began checking resistances to ensure that I had continuity, and I found something interesting.

The resistance from the bullet-connector on the wire that powers the bulb (light green) to the terminal on the switch was about 0.2 ohms....so, good continuity for the power wire. The resistance between the switch body and the ground connection was also about 0.2 ohms....so, the switch is grounding properly on the column. Then I checked the resistance from the bullet connector on the light green wire all the way to ground, and got 18.5 ohms...hmmm.

After a bit of head-scratching, I've now determined that the resistance across the replacement bulb from MiniMania is 18.2 ohms! This sounded way too high to me, so I checked a tail-lamp bulb, and measured 0.6 ohms.

If I'm thinking about this correctly, the high resistance of that bulb would create a very low current flow, and prevent it from lighting up on the voltage pulses. Does this sound logical?

[minimans]

If you have it off the switch try it directly on the flasher unit output? if it works there then it's something else

[Benny]

If you have it off the switch try it directly on the flasher unit output? if it works there then it's something else

Good idea. I connected the bulb directly to the flasher this morning, and it behaved exactly the same as it did in the switch....one little flash, and then dead. Seems like I've found the culprit.

I spoke to a buddy at work who is into model trains, and he is going to make me up an LED this evening that he says will be suitable. We'll see what that does.

[minimans]

It's likely to be a faulty flasher unit the repeater function doesnt rely on the load side.

[Benny]

It's likely to be a faulty flasher unit the repeater function doesnt rely on the load side.

Is there any reason I can't pick up a replacement flasher locally to test it? Are there certain specs that I need to look for?

[minimans]

No nothing special any 3 pin can type unit will work. If the flashers are working correctly on the car then the repeater function should work as advertised unless the unit is faulty.

[Benny]

Ok, I've got this one sorted out....but not without some more head-scratching.

On Thursday night, I pulled the flasher out of my '65 MGB. The car has been sitting for a while, but the indicators should have been working the last time it was driven, as the previous owner was driving it regularly, and the flasher looked brand-spanking-new. I put it on my Mini, and now the switch bulb was staying on constantly! When I'd turn on the indicators, it would pulse dim and bright, but never actually go out.

On Friday, I bought another new flasher, and installed it, and everything works as it should. So, two bad flashers....I guess they are not as robust as I once thought.

By the way, the LED that my friend made up for me also works great, so now I have a choice....old technology, or new technology?

[minimans]

On Thursday night, I pulled the flasher out of my '65 MGB. The car has been sitting for a while, but the indicators should have been working the last time it was driven, as the previous owner was driving it regularly, and the flasher looked brand-spanking-new. I put it on my Mini, and now the switch bulb was staying on constantly! When I'd turn on the indicators, it would pulse dim and bright, but never actually go out.

Another lesson learned here! NEVER use a new or used unit as a test piece unless it has been verified as working correctly 1st!! talk about being led up the garden path....................