Indicator / hazard issue?

[tony g]

After fitting LED bulbs to the indicators with electronic flasher units Im getting an odd problem.
Hazards work perfect but when on indicators all 4 bulbs flash. The side that shouldn't be flashing is not as bright as the other side but still quite bright. This is reversed when switching direction.

At the indicator switch if turning left I put a meter on the terminal that feeds the left and its 12 0 12 0 etc as you would expect, but still turning left when I put the meter on the R/H terminal it reads 5 0 5 0 and so on. This 5v is enough to make the other side flash bright enough to make it look like the hazards are left on. so...when I change the rear bulbs back to filament bulbs the problem goes away.

Can the hazard switch be feeding the indicator switch with the 5v even when not asking for it?

Ive re-earthed rear lamps with new cable and very good earthing point in the boot.
If I disconnect the front lamps the rears still do the same.
I don't think its an earth problem and these bulbs don't need external resistors so could the hazard switch be giving enough V's to the LED's to light them but not enough to light the standard bulbs?

If a new hazard switch would cure this I may have to take a hit on one but Id hate to fit one and find they all do the same ie send some voltage where its not needed.

Any ideas guys?

Cheers

Tony

[geeksteve]

Can the hazard switch be feeding the indicator switch with the 5v even when not asking for it?

Answer that and you'll be on the way to fixing it. Put the original bulbs back in, and put a meter on the side which is off. See if it still does the 5 (even if you can't see it in a bulb).

Steve

[sprint95m]

I have no experience of using LEDs for the indicators, just yesterday happened to read this comment (second post)....
http://www.triumph2000register.co.uk/ph ... =33&t=5466





Ian.

[MIG Wielder]

Can the hazard switch be feeding the indicator switch with the 5v even when not asking for it?

Ive re-earthed rear lamps with new cable and very good earthing point in the boot.
If I disconnect the front lamps the rears still do the same. ( Did you do both at the same time ?)
I don't think its an earth problem and these bulbs don't need external resistors so could the hazard switch be giving enough V's to the LED's to light them but not enough to light the standard bulbs?

Tony

Hi Tony. To answer your first question, then yes if the hazard switch was full of water this would be a possibility. However I think the cause is still due to earthing.
Certainly you have done all the right measurements and tests which are really good, but can you try one more thing please.
Can you remove both front LED indicator bulbs and try again.
Do the rear LED bulbs work as normal ? If so the problem is in the single black earth wire that disappears into the loom under the radiator. ( If this is not earthed the circuit is completed via the sidelight bulbs back to the other LED indicator bulb. The current is a lot lower so the sidelight bulbs may not light.
If not, can you refit the both front LED bulbs and remove both rear LED bulbs.
Do the fronts work as normal ?
If this doesn't fix it I have a couple more ideas.
HTH,
Tony.

[tony g]

Thanks Tony I'll give it a go tomorrow and report back. All the wiring to the front lamps is new and I've had my wiring guy solder as best he can the bullet connector on the back of the lamps. I'll report back cheers

Tony

[tony g]

Right Ive tried a few things this morning:

Removed front flasher bulbs. Rears have LED bulbs. Result: both sides flash - no dash indicator flashing
Fronts then have filament bulbs fitted with rear LED. Result : All flash normally side to side and dash indicator working.
Fronts then have LED fitted and Rears have filament. Result : All flash normally side to side and dash indicator working.
Fronts have LED and Rears have one of each type. Result : Both sides flash.

I then ran an earth via a jump lead from battery Neg to the spider earth on the inner wing (recent clean connection and showing good continuity). All 4 LED fitted. Result : All 4 flash on R/H or L/H indicator setting.

Then I clean the front lamp bodies and connected a jump lead directly to the lamp body and other end to good earth. All 4 flash.(with LEDS)

The earth wire under the rad area that feeds the indicator/side light lamp body (I think), goes into the cabin and to the 5 pin plug that feeds the dash. I disconnected this plug and checked continuity from the loom side to a good earth. All good there. Connected the plug back together. The single black joins to the 2 wire black on the dash side of the plug and this also checks good for continuity.
I'm assuming that this black goes from the dash down to the loom behind the heater and out through the N/S grommet to the spider earth, which is also good for continuity.

A thought: Can the bulb in the flasher switch create a problem here? Giving the red switch a twiddle sometimes makes the bulb go out while hazards are on although it doesnt stop the main bulbs flashing..

As an aside Ive fitted new fuse boxes that have little led bulbs to show when the fuse is blown (or missing) While the hazards were flashing I pulled this fuse and the little led on the fuse box was flashing even though none of the indicators were flashing, including the switch itself. I'm guessing as the Hazard switch is fed with permanent live it feeds straight into the flasher unit?

Sorry if its a bit long winded but thats about where Ive got to.

Cheers

Tony

[Toledo Man]

The hazard switch does have a permanent live. It also breaks the circuit for the indicator stalk when it is switched on so that the indicator stalk doesn't work when the hazards are switched on. Just one question: Are your LED bulbs the amber ones? If you use the bright white LEDs the colours through the lenses look a bit pale and washed out. I reckon that warm white LED bulbs (if they're available) would fix this problem because the light they produce is similar to filament bulbs.

[tony g]

The bulbs are amber. They look great through the lens,real deep colour. The stop/tail ones are red when lit and also look really good through the lens. The front sides are less of a joy, they have a blue tinge to them which doesnt look as nice as the original. The festoon interior is really bright and white

Tony

[MIG Wielder]

Right Ive tried a few things this morning:

A thought: Can the bulb in the flasher switch create a problem here? Giving the red switch a twiddle sometimes makes the bulb go out while hazards are on although it doesnt stop the main bulbs flashing..
Cheers

Tony

Hi Tony; The light has dawned on me as to what the problem is. And may I say that was a really good series of diagnostic tests you did.

Can you dive behind the instrument panel and remove the bulb from the Direction Indicator Warning light please. This is item 48 on page 86-7 of the Sprint workshop manual.
Does this fix the problem ?
( This does assume you have a post VA15001 model Sprint )
If this is a fix, then we have to come up with a solution to the not-having-a-warning-light problem for the MOT.

If it isn't a fix its back to scratching the skull time again.
I'll do an explanation as to why in a mo.
Cheers for now,
Tony.

[tony g]

Thanks Tony I'll give it a try and report back.

Tony

[tony g]

So removing the dash flasher bulb has cured the double flash

What's your theory Tony?

[MIG Wielder]

O.K. so we now have a confirmed cause.
The problem with swapping to LEDs on a post VA15001 Sprint is caused by the way the B.L. electrical guys wire the dashboard indicator pilot bulb.
You don't get this on the early cars as the left and right dashboard bulbs were separate and simply wired in parallel with the main indicator bulbs.
So what they did to get the single dashboard indicator bulb to light was to wire it between the output sides of the external indicator bulbs. i.e if you operated the offside indicator, the +12 V supply from the offside was connected to one side of the pilot bulb and the return to earth was made via the nearside bulbs. Now, you would think that this would cause the nearside bulbs also to flash, and you will certainly detect a small voltage on the bulbs, but the small current ( 110mA ) of the pilot bulb is not enough to get the nearside bulbs to light. ( About 2A.)
Swapping to LED indicators changes all this as their drive currents are much lower. From Tony's measurements I would reckon about 150mA. So the full brightness current of the GLB 280 110mA pilot bulb is a significant proportion of this. Hence the problem.
So we need a solution : Preferably one with minimum wiring changes.
Changing the indicator pilot bulb also to an LED unit might help but it would need to be very low current and it would also have to be bi-polar . i.e. it still works whichever way round current passes through it.
It needs to be low current to stop the non-operational side from working and needs to be bipolar because the direction of current through it changes depending on which side of the indicators is operated.
Can you find a low current LED version of a GLB 280 bulb with bipolar characteristics. This could be done with 2 LED elements back-to-back or one element in a bridge rectifier arrangement.
A more messy solution would be to wire a relay ( must have a diode across the operating coil ) with 2 steering diodes from each side of the indicators and using that to drive the pilot bulb.
Another solution would be to wire 2 x 21W indicator bulbs in parallel with the external LED bulbs to sink the pilot light bulb current. And then hide them out of sight. Or use 2 x 5.6 ohm 25W resistors to do the same job.
Ref; Page 86-7 of the Sprint workshop manual. Note the error in the labelling of item 47 as the headlamp flasher switch.
HTH,
Tony.

[tony g]

Wow Tony thanks for the detailed explanation!
Firstly I will try the led bulb for the dash and see if that works first, if available. As an example the 21w equivilant flasher bulb consumes 0.21 amps and the 4 w front side light bulb consumes 0.04amps. So the little dash indicator bulb would take very little too. Adding resistors would be my second option. Would the resistors you've mentioned be ok just on the rear feeds or all 4?

Thanks

Tony

[Jon Tilson]

Genius diagnosis Tony. I never thought of the ganged up pilot bulb....now it all makes perfect sense.

Even though I've been quiet on this one its been doing my head in....and could offer nothing other than earth returns via side lights
combined with a dodgy earth at the side light unit backplate.

Nice one.

Jonners

[tony g]

a quick update: Thanks to Tonys diagnosis ive spoken to the guy I bought the LED's from. He is here http://www.dynamoregulatorconversions.com/
Straight away he said yes the single dash warning light is the problem and he sells a repair for it. It's a few pieces of wire with diodes attached just as Migwielder predicted. So Ive ordered one and will update the thread once ive spliced it in to the back of the dash.

Tony, thanks again for leading me in the right direction

Tony