ARC problems

3567 Views 20 Replies 14 Participants Last post by kredden, Feb 2, 2008

gkrumian

Discussion Starter · Jan 26, 2008

Lately I am getting ARC christmas light show mostly when I put my foot on the brake. The ARC has been perfect all along. The only thing I did recently was replace one of the burnt out bulbs. Is there something I can check quickly and is the brake pedal connection a good hint of where to look?

Gary

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Incompatible

· #2 · Jan 27, 2008

ARC xmas lights

Please be a little more specific.
I assume that when you press the brake more that one light on the ARC is coming on ?
If this is the case check the ground on the ARC and double check the connector.
Maybe you did not push the connector all the way in when replacing the bulb or bent a pin ?

I attached a trouble shooting guide in pdf format

Marc

Pictures of my Milano and Spider can be seen on the link below
Spider

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Gubi

· #3 · Jan 27, 2008

I seem to recall reading somewhere that if you use the wrong wattage bulb in the brake lights it can mess up the ARC, but I can't find the reference.

Does your car have wear sensors on your current pads? If so and the pads are at limit, that would also cause a signal to the ARC when you touch the brakes.

FlyGirl

· #4 · Jan 28, 2008

I have the same problem in my car. It was the worst when it was cold out. The lights would have no rhyme or reason as to why and when they turned on. They flashed all the time even though doors were closed, oil was fine and brakes were new.

People say that the ARC has a ground problem, but we tested it and it was fine. We tried everything to get the light show under control

, but ended up just disconnecting it.

I know this doesn't help...maybe just knowing your not the only one...and if you figure out what's going on with it, pass the knowledge down

alfaspence

· #5 · Jan 28, 2008

i know its of no help, but ive done away with mine completley

(including unit behind glove box)

sh0rtlife

· #6 · Jan 28, 2008

ever so slightly off topic...are there any "good" reasons to keep it?like actualy "useful" information

...i had intended to re-use mine in my "project" but with all the error issues ive read about im questioning it

Rookie ROX

· #7 · Jan 28, 2008

I was always under the impression that things like the rear lights ran directly through the ARC - Removing the ARC control unit would require lights to be rewired. You could take out the display, but it's probably worth keeping the control unit.

ROCK ON
R~R

gkrumian

Discussion Starter · #8 · Jan 28, 2008

In my other Milano, I had disconnected the unit from behind the glovebox. The Verde is in such good shape that I would like to keep everything working on it. I'll play with the connectors and see if that helps.

AR4me

· #9 · Jan 28, 2008

Rookie ROX said:
I was always under the impression that things like the rear lights ran directly through the ARC - Removing the ARC control unit would require lights to be rewired. You could take out the display, but it's probably worth keeping the control unit.

ROCK ON
R~R

Agreed !!! If you remove the control unit above the glove box you will no longer have brake lights

I forget if other rear lights are affected as well.
Jes

fraz

· #10 · Jan 28, 2008

I have finally tired of this so bad I have been entertaining cutting a custom piece of carbon fiber to cover it up LOL!!!

Don't know if I mentioned it but everybody that gets in my car has to ask about the blinking lights. One of my friends got in and pointed and said "What is that like KITT**?" Without missing a beat I replied with "Uhh, no that's more like KITT's retarded brother" (hangs head in shame)

**KITT==talking computer car from the 80's TV show "Knight Rider". "Knight Rider" (1982)

JoeCab

· #11 · Jan 29, 2008

sh0rtlife said:
ever so slightly off topic...are there any "good" reasons to keep it?like actualy "useful" information

I guess my experience has been atypical, but all 3 of my Milanos have had a functioning ARC, hot or cold, winter or summer.

When a warning light went off, I would check why and fix the problem. I agree that most of the functions like the warning lights for 0.brake pad wear and oil level are not necessary if you pay attention to your car's health. But, some things like the warning for burnt out lights, low wiper fluid level, etc. can be useful.

IMHO, if you get the light show it's usually bad grounds or low overall system voltage.

Joe

alfaspence

· #12 · Jan 29, 2008

AR4me said:
Agreed !!! If you remove the control unit above the glove box you will no longer have brake lights I forget if other rear lights are affected as well.
Jes

spot on! if you remove the control unit you will lose all sensors, parking lamps, side markers and brake lights... oh and your tacho too

removal of the unit will require rewiring! (unless you just unplug the conector to the unit and rear of ARC panel) it has direct feed via i think 5 maybe 6 wires

gkrumian

Discussion Starter · #13 · Jan 29, 2008

I plan on finding the source of the light show but I'm confused with why some have experienced that removing the ARC control unit disables all the lights. I had done that in my older car and everthing still worked with no rewiring.

AR4me

· #14 · Jan 29, 2008

The control unit is separate from the ARC display. The control unit sits above the glove box (unscrew the 3 little screws and pull down the lid). The ARC display itself (at the ashtray) can be safely removed.
Jes

Rookie ROX

· #15 · Jan 29, 2008 (Edited)

gkrumian said:
I plan on finding the source of the light show but I'm confused with why some have experienced that removing the ARC control unit disables all the lights. I had done that in my older car and everthing still worked with no rewiring.

As Jes has stated, removing the display won't do anything, but the control unit will.

If you look at the wiring diagram I've attached, it's off the rear external lighting. Every marked as an 'E*' is a light, if you follow them you'll notice they all juncture at the large box on the top right labelled 'N22' - N22 is the ARC Control Unit, and then C11 is the ARC Display. So you can see from that why you can remove the display without drama, but taking out the whole box itself will kill a lot without rewiring. Worth it in something like JJ's 3.7 where he replaced everything with a Painless Wiring kit, but hardly worth it for any street or general track car imho.

Usually though, the light show is always caused by bad grounds. If it's a single continual light, it normally means either (a) you actually do have a problem with whatever is being indicated or (b) the sensor itself has failed.

ROCK ON
R~R

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Rick7520ts

· #16 · Jan 31, 2008

I know of people who had che cristmas tree ARC only in winter with cold temps, they solved the problem simply by changing che ARC control unit and/or display. I don't know why but there are some that below a certain temperature do not work any more.
I have the same problem on my car, but I haven't had the chance to find replacement parts.

romroc

· #17 · Jan 31, 2008

Can someone please send a wiring diagram of the ARC? When new they worked well, but as the cars age I see the ARC tends to arc and misfire.

Gubi

· #18 · Jan 31, 2008

I've opened two control units up and in both of them the traces on the PCB were all wrinkled and peeling away from the surface. I think they just weren't made very well.

Craig

· #19 · Jan 31, 2008

Tom,

I'm looking at one now and although it looks like that it's actually solder on top of the tracks that gives the wrinkly look.

As for wiring diagrams, for the control box and display as far as I know no such animal exists in the public domain

but the interface of both to the car is in the Alfa 90 Group 43 manual on my site.

alfaspence

· #20 · Feb 1, 2008

i have another variant of wire diagram (milano specific) but not for the internals of the control unit itself unfortunatly. similar to Craigs but there are variants on the terminals between models and markets apparently (i have gone into this in quite some depth with my car!)

for most things its a case of simple "in and out" of the control unit (particularly lights and door switchs)

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