LED Idicator ballast question

[James1979]

May belong in Automotive- please move if it’s in the wrong place.

After I’d finished swearing about some unknown c0ckwomble smashing the light on my truck in Tesco, I went and got new combination clusters for the back end. (2 because you can’t buy the ones I have anymore - different rant)

From the local factors, not Chinese crap online. Tested them before they went on, on a 12v source. All is good.

Put them in, and I can’t get indicator. Will come on with hazards. So it’s obviously (?) a loading issue. They’ve got the ballast resistors in parallel.

Tried disconnecting the resistor and they flash for a few then give up.

Put a power probe straight to the lamp and alls fine.

Are the resistors available in different resistances does anyone know, please, and how do you determine which you need? I know I’d choose to do it with a variable resistor then measure that, but I don’t have one.

 

[jsf55]

Is it the old can type flasher unit ? it might be worth swapping it out for a electronic one as there not effected by load ?

 

[James1979]

Is it the old can type flasher unit ? it might be worth swapping it out for a electronic one as there not effected by load ?

I don’t think so as it’s an 12 plate L200 and it had aftermarket LEDs on the back before.

Good point and I will investigate. I’m expecting to find it’s not a flasher ‘unit’ but all done in the body control module

 

[Blobber]

^^^^ this, worth checking first and cheap to replace

 

[AKN]

A 21W bulb when lit would be equivalent to a 6.8 Ohm (standard size) resistor but it would need to be rated for 25W or more to stop it burning out.

Is it the old can type flasher unit ? it might be worth swapping it out for a electronic one as there not effected by load ?

All flasher unit are load sensitive, construction and use requirement, to give bulb fail indication. Old style, bimetallic, tend to stop flashing, electronic ones flash at twice the rate.

 

[James1979]

A 21W bulb when lit would be equivalent to a 6.8 Ohm (standard size) resistor but it would need to be rated for 25W or more to stop it burning out.


All flasher unit are load sensitive, construction and use requirement, to give bulb fail indication. Old style, bimetallic, tend to stop flashing, electronic ones flash at twice the rate.

It’ll be an electronic one then. It’s failed to flash fast

 

[Matrixx]

sure its not a can bus issue?

 

[James1979]

sure its not a can bus issue?

Not ruling that out.

It’s a utility truck body and they’re notorious for being a nightmare, electrically. Considering what Strongs charge for these, the electrician wants violating with a rotating cactus.

I’m no auto electrician but the standard of electrical work in these is atrocious. Although it’s common in bodybuilding it seems. Lorry’s with aftermarket bodies are often no better.

I’m working on it now so I’ll report back.

 

[hotponyshoes]

Measure the resistance of the old light unit and compare that to the new ones.

 

[James1979]

Seems I didn’t realise / pay attention when I picked them up but they are “dynamic” indicators. They need a constant voltage to work as the flasher module is in the unit.

I think they work for a couple of seconds initially due to a capacitor or something inside?

Anyway. That appears to be the issue. Next problem. How do I (cheaply, easily, reliably) convert flashing to a fixed voltage? Already fitted them so they can’t go back.

Worst case I’ll buy non dynamic ones and either sell these or work out how to make them work and keep them for a trailer or sommat

 

[Kram]

Already fitted them so they can’t go back.

Not fit for purpose, of course they can go back.

 

[hotponyshoes]

How were they working with the hazards on?
Flashing normally or dynamic?

How about on the 12v source?

 

[James1979]

How were they working with the hazards on?
Flashing normally or dynamic?

How about on the 12v source?

They are now working, sort of, on normal direction indicator. Work on dynamic but will miss a beat every 10 or so flashes. Don’t work the first 2 then fine. So it’s like there’s a cap inside that’s charging?

Don’t work on hazards.

I can hear a flasher unit clicking somewhere in the body conversion so I’m going to try and dig that out and see. Why there’s a second one I’ve no idea but…..

Work fine on 12v source / powerprobe.

I’m not bothered about hazards if I can get direction indicators for now as I’ve strobes all over the thing so hazards aren’t a big deal except for MOt

 

[hotponyshoes]

Where have they picked up the wiring for the rear body lights?
Off the original rear light looms or from a bodybuilder plug?
Or the Towbar wiring or something?

 

[James1979]

Where have they picked up the wiring for the rear body lights?
Off the original rear light looms or from a bodybuilder plug?
Or the Towbar wiring or something?

Original looms I think.

Then to trailer control module which is another world of pain I’m playing with.

Problem with these little trucks is they don’t have a bodybuilder socket normally so people just cut stuff in

 

[500e]

I feel your pain, the dam things have got to complicated

 

[jsf55]

You can always add load by just putting a bulb in series ... or is parallel,

 

[James1979]

I’ve put a 5ohm resistor in which is standard but no dice.

Poxy thing!!

If I get time ( ) over Xmas I’m going to pull all the wiring out so it’s back to standard then rewire the body properly.

For the money these cost it’s appalling. I wouldn’t go to them!