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I've just noticed this week that when I turn my lights on at night, my rear fog lights come on straight away, as I turn on the headlights. They go off when I press the rear-fog button, but something somewhere is making them come on automatically when I switch on the normal dipped headlights (and no - they weren't left on when I turned the lights off previously).

It doesn't do it every time, but has done it on several occasions in the last week.

One thing that really annoys me is drivers who have their rear fog lights on unnecessarily, but I'm afraid I've become one of the culprits this week, unwittingly!

Has anyone any ideas? :confused:
 

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CAN-bus electrics can have some strange problems.
Probably just needs everything resetting with the Examiner diag system.
 

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It might be worth checking the wiring loom leading to the rear fog light in the boot area, and also the lamp unit itself to make sure something isn't causing a short circuit. Also check that you have the correct bulbs fitted and nobody in a service station or alike have but in the wrong type.

Thats assuming you haven't already ;)
 

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Alfiejts said:
I've just noticed this week that when I turn my lights on at night, my rear fog lights come on straight away, as I turn on the headlights.
It doesn't do it every time, but has done it on several occasions in the last week.
Hi, just saw your post on this. Mine does the same, 2004 156 2.0JTS SW. It seems to do it only on cold damp mornings, the colder and damper, the more likely it will happen. Sorry to hear you've got this too but glad I'm not the only one.

I'm gonna have a look at the wiring and bulb housing this weekend, if I find anything I'll post, if not I'll probably just wait until the service and get Alfa to have a look.

has.mac
 

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I may have commented too quickly on that one. The tacho on a 2.0 JTS issue causes one of the rear brake lights to glow. A fellow mechanic that works at an Alfa dealer was telling me about how long it took to figure out the problem. I don't know the details but I will ask.
 

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I may have commented too quickly on that one. The tacho on a 2.0 JTS issue causes one of the rear brake lights to glow. A fellow mechanic that works at an Alfa dealer was telling me about how long it took to figure out the problem. I don't know the details but I will ask.
Was there ever a follow up on this- I have just become a victim of this- on my 1.8TS SW. . .:(
 

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The issue here (and it has lots of threads on this forum) is that the "bulb out" detection circuit is controlled by an IC chip on the tacho - if this IC chip blows or faults it tends to leave one of the rear lights on all the time causing a permenent drain on the battery.

There are only two fixes for this;
1) (Easy) Replace the Rev Counter - one screw for the suround, two to release the tacho.
2) (Harder) Replace the blown IC chip - needs good soldering skills for this - this is a detailed explaination in other threads which also advises which chip is needed and where to obtain.

Just do a search on "156 Rev Counter Issues" - this is only a 156 issue not a 147 one.
 

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Ok cool- thanks for this update. I'll have a search. Apologies if this is an oft discussed topic. I'm new to Alfas (but coming in from fiat coupe ownership, and club forum member), so I'm still getting to know the car. Hopefully I'll be able to share info too as much as I can.
I did some extensive googling yesterday and found suggestions that it was the taco, and a smidge of a wiring diagram. I've just bought the factory manual too so hopefully I don't bug people with too many newbie questions.
I'll traw your suggested tag, and update y'all with how I progress!
nick,
 

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Happened to me too...

I fixed it by removing the bulb and cleaning the metal leads with wd-40.
A good clean is a must. It gets rusty over time and causes conductivity problems.
Hope this helps.
 

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No not the tacho... Actual lamp in the boot area.
You should open your boot, and unscrew the back part of the rear fog light..and reach the bulb..then spray/clean the contacts.

--
Selim G.
 

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Alfa 159 2.0 JTDm Lusso 6sp.
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I have the same prob on my V6. I KNOW its the tacho as i borrowed one from a friend to replace mine and it cured the prob. My rear fogs come on when I go from dip to main as well as when I first turn lights on. I have noticed that if the front fogs are on this does not happen!!! God bless Italian electrics.
 

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I also have this problem. I guess I need to find a replacement rev counter then.

I checked the bulbs and the contacts they looked fine to me, good clean contact.
 

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Me too as I had to give mine back to its owner and put mine back in. Think they are about £300 from Alfa. A few used ones on Ebay but why are they there if they work properly!!!!?
 

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I cleaned up all the rear bulbs yesterday, and the problem has gone from constant to intermittent.
I bagged a replacement tacho off the bay, from a guy breaking a complete car, so I have that as a standby spare. . .
Hopefully the WD in the contacts will help, and as the big freeze here is thawing- I wonder if that is helping too. .
 

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I cleaned up all the rear bulbs yesterday, and the problem has gone from constant to intermittent.
I bagged a replacement tacho off the bay, from a guy breaking a complete car, so I have that as a standby spare. . .
Hopefully the WD in the contacts will help, and as the big freeze here is thawing- I wonder if that is helping too. .
Elite504:
There are 2 switches for the fog lights by the handbrake. Just take out the plastic, and spray WD40 on the contacts underneath.. That way, I hope you can fix the problem for good.

Have a good one.

--
Selim G.
 
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