Alfa Romeo Owners Club of Australia Forum

Technical => 160 Series (90, 75, 164 Sedans) => Topic started by: GTVeloce on July 16, 2021, 12:56:09 PM

Title: ARC correction for LED lights?
Post by: GTVeloce on July 16, 2021, 12:56:09 PM
Has anyone managed to correct the ARC when it thinks a bulb is down due to LED lights? I want to mention my ARC is working correctly - no Christmas tree lights going on. I installed LED lights almost everywhere (except headlights) which are so much better than the originals but of course the ARC thinks I am down a bulb. I know I could correct it by installing a resistor next to every light but that is a lot of resistors! I'm hoping I could install fewer resistors by installing them on the input to the ARC instead.

Has anyone managed to do this?
Title: Re: ARC correction for LED lights?
Post by: Craig_m67 on July 16, 2021, 03:35:52 PM
Remove ARC lamp/led from dash... you're effectively negating it anyway
Title: Re: ARC correction for LED lights?
Post by: GTVeloce on July 19, 2021, 10:21:44 AM
Quote from: Craig_m67 on July 16, 2021, 03:35:52 PM
Remove ARC lamp/led from dash... you're effectively negating it anyway
A possibility but not my preferred course of action. The ARC does work in every other way and I believe if I get the resistor values correct I could still have the ARC working for lights i.e. a bulb failure will illuminate the ARC.

I'm confident I could do it if I placed a resistor on every light but that is 12 resistors (by my quick calculation) that I need to splice into the wiring loom. Given I am not sure yet of the value required (I plan to install a pot first and the determine the value from that) it's a lot of stuffing around. If only I could splice into the ARC instead - one connection instead of 12.

This also raises another issue and whether the combination of 12 resistors in one would generate too much heat given the location of the ARC? I'd prefer not to burn the car down just to fix a few flashing lights...
Title: Re: ARC correction for LED lights?
Post by: Colin Edwards on July 19, 2021, 11:33:55 AM
Looked into this myself for a while as I've also replaced a few incandescent globes with LED's on my 75.  I suspect the ARC looks for what will effectively be a dead short across the globe sensing input.  A cold filament will feature an extremely low resistance until it heats up / glows white hot.

A say 6W globe will rapidly increase in resistance from near 0 ohms when cold to 24 ohms when hot / at full brightness. 
To stooge the ARC into "thinking" all globes are intact will require very low value resistors at each globe.  If say that resistance is as low as 2.2 ohm, we need a 65watt resistor!!  With 12 of these scattered about the car, total wattage needed is 785W!!  We would be consuming and wasting more power than we save by installing LED's in the first place.  Not to mention the heat created.
Better to locate the discrete input to the ARC at the ARC itself.  Its probably one of the 2w carbon resistors on the N22 pcb.  I've tried to trace this out more than once, however the schematic and what's on the car don't seem to add up!!!  Its still on the "to do" list.

Title: Re: ARC correction for LED lights?
Post by: GTVeloce on July 22, 2021, 10:15:41 AM
Thanks Colin. Yes, like you, I have tried a few times at the ARC but the schematic isn't accurate and not quite as comprehensive as I would like. If I had a spare ARC I would open it up and experiment on that but I don't. Hence I was hoping I could piggyback off someone else's hard work  ;D

Looks like I am going to have to do the hard work  ::)
Title: Re: ARC correction for LED lights?
Post by: shiny_car on July 22, 2021, 12:03:42 PM
Very happy for you to do the hard work  ;D .

I'll be quite interested to hear of any success, as I want to fit LEDs for indicators and brake lights, depending upon how bright they look.

I don't have electronics skills, just general auto electrical skills.
Good luck!
Title: Re: ARC correction for LED lights?
Post by: GTVeloce on July 26, 2021, 11:34:33 AM
Looks like I'm going to have to roll up my sleeves!  ;D

I've put LED indicators (along with an electronic flasher unit) and they are much brighter than original. Highly recommend it. I've also replaced front park lights, rear park, stop, reverse, rear fog, number plate, boot, bonnet, dash, overhead dome, glovebox, clock, cigar lighters, ash tray...have I missed anything?! The only bulbs I've not replaced with LED are headlights (provided you upgrade the wiring and add relays they are fine) and the front fogs. Contemplated turning the front fogs into LED driving lights and hard wiring them to the ignition to run as DRL but haven't made it that far yet.
Title: Re: ARC correction for LED lights?
Post by: bteoh on July 26, 2021, 05:35:23 PM
Would be interested in LED lights for the indicators and would like brighter lights esp in the rear as they are woefully dim when flashing. Let us know what you used and where to source them from?
Thanks :)
Title: Re: ARC correction for LED lights?
Post by: GTVeloce on July 26, 2021, 08:59:16 PM
I have bought most of my bulbs (including the indicators) from here;
https://www.ledshoponline.com.au/shop/
I have tried to buy the brightest bulb possible so if they have a BA15S Hi-Power version that's the one I have gone for.

I have also bought a few of the internal bulbs from a random ebay store and some from Stedi.

I have also changed all my bulbs except the indicators on my Alfetta GTV and am very happy with the result. I have bought the indicators but haven't got around to changing them yet as there is a little fiddling required to get the flasher unit to work. I had to do the same with the 75 but the indicators in that are far worse on a 75 than a GTV.
Title: Re: ARC correction for LED lights?
Post by: Colin Edwards on July 27, 2021, 09:46:24 AM
+1 for ledshoponline.com.au

Replaced all parking globes, indicator globes, interior globes in headlining and rear numberplate illumination globes.
Title: Re: ARC correction for LED lights?
Post by: bteoh on July 27, 2021, 03:43:16 PM
Thanks guys.
Anyone tried this company :-  https://www.eslights.com.au/

They claim that these are the brightest on the market :-  https://www.eslights.com.au/product-page/2x-2021-xstorm-1156-ba15s-canbus-inicator-turn-signal-led-bulbs
Title: Re: ARC correction for LED lights?
Post by: Colin Edwards on July 27, 2021, 05:02:02 PM
Before spending a heap of folding on LED's, need to remember the alternator is the final source of power to drive the lights.
 
The process of engineering a right hand drive version of a largely left hand drive car meant the RHD 75 wiring loom is a modified LHD wiring loom.  End result is additional connections and cables in the circuit from the alternator to the fuse panel.  Although a fair bit of work (ask me why I know!), simplifying the circuit and replacing with cable 3 x times the cross section of the existing makes a huge different to the voltage ultimately fed to all the 75 electrics including the lights.  This cable also needs to be as short as practically possible.  Its critical the cable from the alternator to the fuse box is capable of conducting the required current with minimal voltage drop.  Its the voltage drop between the alternator and the fuses that dulls the lights.

Also need to ensure the alternator is up to the task.  Most club sponsors should be able to lay their hands on replacement regulator / rectifier assembly for the alternator.  These are usually supplied with new brushes.  As long as the bearings are ok, the alternator should be ok for another 150,000klm!
Don't polish the alternator slip rings with ANY abrasive.  The slip ring surface should be a similar colour to the surface of the carbon brush - if it is its in perfect condition. 
Title: Re: ARC correction for LED lights?
Post by: GTVeloce on July 27, 2021, 08:59:37 PM
This is my 75 with the led store rear lights and number plate lights. Note, this is not my brake lights (they are even brighter!), just the rear park lights.
Title: Re: ARC correction for LED lights?
Post by: GTVeloce on July 27, 2021, 09:04:01 PM
And this shows the interior dash lights and the overhead dome light. There is no extra lighting here - this is how bright it is at night with the doors open. You can also see the front park lights reflecting off the fence.
Title: Re: ARC correction for LED lights?
Post by: bteoh on July 27, 2021, 11:56:22 PM
Wow, that is super nice. Did you get most of the globes from ledshoponline? With the dashboard leds, did you get any problems with the ARC warning lamps? Or indicator BA15s leds?
If no problems, I will do the same as they are cheaper compared to the other store.
Cheers :)
Title: Re: ARC correction for LED lights?
Post by: GTVeloce on July 28, 2021, 10:18:53 AM
Yes, most were from ledshoponline although the cluster lights I think were from Stedi, who also make excellent lights. I would happily buy again from either however Stedi is more focused on bigger lights like led bars and spot lights. Their range for small bulbs are much smaller.

I don't believe the dash board lights are connected to the ARC IIRC. I updated them after I had installed led front park lights so many warning light was already on.

The indicators won't affect the ARC but you will need the electronic flasher unit (ledshoponline sell them) or you will get hyper-flashing. And it's not a drop-in - you will need to alter the wiring slightly as the number of pins are different between the original and electronic but it's not too hard.
Title: Re: ARC correction for LED lights?
Post by: bteoh on July 28, 2021, 05:18:29 PM
Ok thanks.
I have ordered the globes from eslighting as their description for the indicator globes mention no hyper flash problems.
Will report on how effective they are when I get them.
Title: Re: ARC correction for LED lights?
Post by: shiny_car on July 28, 2021, 07:37:49 PM
Quote from: GTVeloce on July 28, 2021, 10:18:53 AMThe indicators won't affect the ARC but you will need the electronic flasher unit (ledshoponline sell them) or you will get hyper-flashing. And it's not a drop-in - you will need to alter the wiring slightly as the number of pins are different between the original and electronic but it's not too hard.

Thanks for the info!

Which flasher unit suits the 75? I haven't investigated.  2-pin or 3-pin?  I presume the 3-pin.

https://www.ledshoponline.com.au/product/12v-electronic-flasher-3-pin/
Title: Re: ARC correction for LED lights?
Post by: GTVeloce on July 28, 2021, 09:29:52 PM
Hm, it's not quite so straight forward. The 75 flasher is 4-pin! I bought the 3-pin and played around until I got it to work however I ran out of time and didn't quite finish the job... so I never got the indicator indicator (the light on the dash) working but everything else works. The sound is loud enough (without being annoying) that I manage without the light for now but have always planned to finish the job off. When I get a chance I will check my wiring and let people know which connections to make.
Title: Re: ARC correction for LED lights?
Post by: GTVeloce on July 28, 2021, 09:39:38 PM
Quote from: bteoh on July 28, 2021, 05:18:29 PM
Ok thanks.
I have ordered the globes from eslighting as their description for the indicator globes mention no hyper flash problems.
Will report on how effective they are when I get them.
Curious to see how they go. I'm guessing they must have built in resistors to stop the hyper-flashing which means they must still draw 21W. The advantage of the electronic flasher is that you can chop and change bulbs (led or not) and the flashing speed should stay the change.
Title: Re: ARC correction for LED lights?
Post by: shiny_car on July 29, 2021, 07:27:59 AM
Quote from: GTVeloce on July 28, 2021, 09:29:52 PM
Hm, it's not quite so straight forward. The 75 flasher is 4-pin!

Ok, thanks!  I'll have a look at the wiring diagram too.
Title: Re: ARC correction for LED lights?
Post by: GTVeloce on July 29, 2021, 06:50:37 PM
My connections are 37 - 49; 39 - 49a; 59 - 31. First number is on the fuse box and second number the pin on the flasher unit. This works however, as mentioned before, the warning light on the dash is not connected.
Title: Re: ARC correction for LED lights?
Post by: shiny_car on July 30, 2021, 05:43:08 AM
Unfortunately, the numbers don't mean much to me right now (sorry!) without seeing the fusebox and flasher in person.  I'll get around to looking at the fusebox some time in the future!!

The ledshoponline website says the 3-pin flasher 'replaces' a Narva 68238.  This is the Narva schematic:

(https://i.imgur.com/mqhfUNv.jpg)

So basically, there's a +12V power feed (B), a ground connection (E), and an output wire that goes to the indicator stalk (L).  The wire to the stalk (L) is also designed to feed the dashboard (pilot) light.

Indeed, all you need to do is identify the wire feeding the dash light, and connect it with the wire feeding the stalk (L).

From this labelled and cropped image of the workshop manual wiring schematic:
- I24 (green circle) is the flasher unit
- B6 (blue circle) is the indicator stalk
- wire BN (blue arrow (white with black stripe)) feeds to the stalk (ie: the 'L' wire)
- D2 (red circle) is the dashboard (pilot) light
- wire AN (red arrow (light blue with black strip)) feeds to the D2 light

(https://i.imgur.com/GRK38xK.gif)

Thus, you might be able to cut or disconnect the AN wire and join it to the BN one, and it should be all dandy!  I suspect actually finding the wires amongst the mess around the fusebox will be the hardest part.

Anyway, I'll go order a flasher now.   ;D
Title: Re: ARC correction for LED lights?
Post by: GTVeloce on July 30, 2021, 10:42:38 AM
Good work Shinycar! Like you said, working out the wires in the back of the fusebox is a bit scary!

I remember at the time (I did this 18 months ago) that I worked out what the numbers meant on the flasher and I've found them again on the Narva site;
https://www.narva.com.au/resources/flasher-application-guide

Essentially: 49 = +ve 12V. 49a = lamps or switch. 31 = earth -ve

From memory I used a multimeter to work out what I figured each pin on the fusebox should do (+12V and earth were easy - the rest were deductions) which is how I got where I got. I doubled up the 49a connection to try and get the dash light to work but IIRC it just made the indicators stay on solid, rather than flash. And then I ran out of time to get further and haven't got back to it. What's 18 months here or there?!
Title: Re: ARC correction for LED lights?
Post by: GTVeloce on July 30, 2021, 10:52:14 AM
This is the schematic for the flasher for a GTV/6 (according to Narva) which is slightly different, but essentially operates the same and has the same numbers as the electronic flasher from ledshoponline. Given I haven't done my GTV upgrade yet (although I have all the parts) this could make life easier.
Title: Re: ARC correction for LED lights?
Post by: bteoh on August 08, 2021, 11:13:51 AM
Just got my BA15s LED indicator globes. Unfortunately, I got hyperflashing on the RHS. For some reason the left seems ok. Looks like I will have to mod the flasher unit to an LED one 😀
Thanks for the schematic diagram which will make it easier 😀