Technical Punto Mk2 8v ELX: Dodgy electrics: strange headlights/fog light behaviour

[Ian Bates]

Hi all,

I'm new to this forum but have been lurking a while. Hello.

I wish to benefit from the expertise of the problem solvers within this forum by presenting an electrical issue I have with my Punto. The issue is progressive in the sense this was once a well-functioning car.

Car: Punto Mk2 8v ELX 2002 (left hand drive)

* Main Problem

Strange behaviour of headlights, and headlights with fog lights. Started over 6 (but less than 12) months ago. Intermittent over maybe 4-6 weeks, now consistent.

1. When driving/engine running with no lights or position lights there is a buzzing noise, alternating between on and off at about 4Hz, coming from the passenger fuse box. Audibly located to one switch/relay relating to the headlights. With position lights they also flicker.

2. Driving with dipped or main beam (not position) there is no buzzing nor flickering.

2. a) Additionally, the fog light operates from the dashboard switch only with main beam, rather than from both dipped and main.

In all these cases indicators, reverse and stop/brake lights all behave as expected.

Practically I am managing with option 2 (dipped). For at least the last 6 months... But it needs attention. Certainly these signs are enough to fail an MOT.

* Call for diagnosis/solutions

I am open to thoughts and comments at this stage. I am interested in a diagnosis but more interested in a permanent solution and getting it through its MOT...

If you want to know more about the fog light and other perhaps related details, then read on.


* Additional Fog Light Information

4. Engine running, operating full beam (away, not flash/towards), then returning to dipped toggles the fog light status.

I can get the fog light on with dipped beam by combining 4 and 2 a), that is from
(Engine running, dipped beam) operating main beam then returning to dipped switches the fog light on. Operating main beam then returning to dipped switches it off.

* Other Related Information

5. This is a personally imported left hand drive. Making it UK road legal involved swapping the rear light clusters for UK spec and rewiring the fog and reverse. This was carried out in 2005.

6. A towbar has been attached(!) and a socket wired in. This work was carried out in 2008.

7. The LH rear light cluster became damaged which allowed slow water ingress into the luggage compartment and saturated the earth point and the wiring exposed by the wiring in the socket. The light cluster damage occurred around early 2010. The light cluster has been replaced early 2011.

8. A mysterious battery draining problem was attributed to sticky passenger lock triggering the central locking continuously. Practically a security issue. 'Solved' only by disabling the central locking by removing the circuit fuse from the passenger fuse box. This occurred mid to late-2010, around the same time as the strange headlight problem was in its intermittent phase.

 

[Ian Bates]

Hi,

I have been to a local garage to get their opinion.

1. To solve the headlights issue they told me to go to a Fiat dealer to get a new Body Control Module and suggested the cost to be over 500 GBP after fitting and coding. But they could not be sure it would solve the problem.

1. a) the local garage also charged me for rewiring my fog and reverse lights the wrong way (selecting reverse gear and the fog light came on, ditto fog light and reverse light) so I am not so confident in their electrical diagnosis although they have serviced this Punto competently mechanically for the last couple of years.

* Options

If a new BCM would solve my electrical issues I see at least two options

2. a) DIY it. I guess it is necessary and sufficient to have a complete (BCM, ECU, door locks, ignition lock, airbag switch, tailgate lock, fuel cap, key(s?)) set from a donor vehicle. Is this a a viable DIY job?

Cost: parts 100 GPB ish, labour: my time, a weekend?

2 b) Get a Fiat dealer to do the job

Cost: 500+ GBP

3. Scrap it/break it.

* Advice sought

If a BCM would solve these issues is it a reasonable DIY job of a Fiat dealer job?

If Fiat are involved is 500+ GBP the 'going rate'?

Is it worth spending so much on a car of this age? What other trouble is there around the corner involving high spend (clutch, gear box...)


Ian.

 

[Ian Bates]

Hi,

* things I have already tried

1. I've cleaned the luggage compartment earth point and the engine bay earth point just below the battery. No joy.

2. I've cleaned all the bulb connectors in both the rear light clusters (particular attention to the fog light). No joy.

* advice sought

I am hoping optimistically for someone to say 'definitely a dodgy earth'. If so, which one?

Do I need to check cable entry into headlights/rear light clusters, and are there other relevant earth points I should check?

Ian.

 

[s and b]

this is something silly
most electrical problems on cars stem from retro fit
youve had plenty of rear end wiring done so look here
particularly at all bulbs if you can change every one
at the towbar looking for miss wiring if you dont need it chop it out
at the front the headlight plugs give issues too
of course it goes without saying that you need to check all earths look in footwells rear panel n/s chassis leg front and also under the steering cowling

no way would i spend €500

 

[Ian Bates]

Hi,

Thanks for your common sense reply. I was beginning to be swayed to turn to the dark side and approach a Fiat dealer. It feels like something silly but for something silly it is hiding very well. Obviously I am not keen on parting with 500 for something silly which may not even work.

I will act on your suggestions.

Opinions and comments still welcome until this is solved (I will post back on status).


* Opinion sought

Would any rear wiring mods I described damage the Body Control Module to result in the behaviour I have described?

* Action I will take

1. Will change, not clean, all rear light cluster bulbs (I still have the old LH clusters lying around).

2. Will change, not clean, all front light bulbs (I still have old headlights lying around)

1. and 2. will check plugs. I will try visual and wiggle test.

3. I have 'chopped' the rear towbar socket already

4. I will search for remaining earth points. Despite owning Hayes it is still not clear precisely where the earth points are, I'll re-read and post back if I have trouble locating them.

Your words have given me a small amount of hope this can be solved without turning to the dark side.

Many thanks,


Ian.

 

[s and b]

3. I have 'chopped' the rear towbar socket already

go to where this has been incorporated into the loom unpick and neatly tape up each wire with proper electrical tape looking for greeness and general bad housekeeping obviously cutting out the extra wiring loom out to towball,i wonder if scotchlocks were used rather than solder

 

[fingers99]

I would download the manual (may be in the downloads section here, but certainly available on line) and check all the earths (there are many more than the ones you've done). By check, I mean, dismantle, clean, smear with silicon grease or vaseline and re-assemble.

But, yes, check on any retro fitted stuff, too.

 

[DaveMcT]

Before doing anything complicated, make sure all earth are good and that all fuses are contacting properly.
That said tow bar and aftermarket alarm wiring are often culprits.