Glowing Battery/charge Light - A Word Of Warning...

[Anthony 1,003]

One of the 205's (many) common quirks is the battery/charge warning light on the dash glowing faintly at night with the headlights on and interior fan at full speed. Not all cars suffer from it by any means, but a fair percentage do.

 

The glowing light is not generally an alternator related issue and the battery charges as expected. Logically, I figured that the issue was likely down to voltage drop between the alternator and interior of the car, leading to the voltage difference across the two sides of the battery/charge light on the dashboard and thus the faint glow.

 

One of my own 205's has had this issue ever since I bought it and put it back on the road a couple of years back, but with prioritising what time I've had to work on it into more pressing jobs, I'd not looked into the issue any further until last weekend. In my case the exciter wire had been replaced when I redid the sensor loom, so any issue had to be elsewhere.

 

At a glance, everything looked fine with the battery wiring, but when I investigated more closely, the main battery positive cable fell apart in my hand where it joins to the shunt box, the copper really badly corroded/oxidised and the actual terminal was badly fatigued from years of vibration and movement. Given that this cable is unfused and thick enough to carry significant amps for a short period, the results of this breaking in service and shorting out on the surrounding metalwork could have been catastrophic.

 

Rummaging around in the garage I found a couple of spare battery cables left over from 205's I've broken over the years. First one had very similar corrosion and again broke off when I wiggled it with any force, and the other was showing signs of corrosion but did at least pass the mechanical stress test.

 

Deciding at this point that there wasn't much point looking for any other original cables as they were likely to be in equally dubious condition being 25+ years old, I made up a new cable and fitted it.

 

That faintly glowing battery light? Gone.

 

Check those connections folks even if they look OK at a casual glance, because that faint glow could be a symptom of something far more sinister brewing.

[farmer 328 1 Cars]

I managed to get a new + cable and as with you cured this

[jackherer 543]

I had a very similar issue at the alternator end of that cable about ten years ago - http://forum.205gtidrivers.com/index.php?showtopic=80354

 

I've actually just replaced the main battery positive cable and ground cable on my newest 205, unexpectedly it has hugely improved the awful FM radio reception it had! I already had a brand new stereo and a brand new aerial and base and I was about to replace the coax cable as I thought it was the only thing it could be but new main power cables has fixed it.

[pp205 17]

Mine has done this ever since I bought it back in 2004! It's on it's 4th different engine now and although I have changed the gearbox and chassis earths I haven't ever touched the positive terminal wiring.

 

I looked at them today and to be honest they do look grim so will need changing. I've had a pair of quick release battery terminal connectors lying around and changed them as the positive battery clamp wasn't in a good way. Fired the car up and the light has gone! Just did a 150 mile trip (Exeter to Westbury and back) and had headlights on, blowers on full and windscreen wipers on as the weathers been bad and there was no hint of the light!

 

I'll change the actual wiring next week.

 

Thanks for the post Anthony to prompt me to check it out!

[allye 530 3 Cars]

For the lazy ones amongst us (and for me being 70miles away from a 205) can some one please post the length, terminal size and gauge recommended to replace this cable? (Order online)

 

With battery/starter/alternator cables I like to buy professionally crimped terminated cables.

[Daviewonder 533 3 Cars]

Interesting stuff. One of mine has done this since I bought it in 2008.

 

I seem to remember one of my others doing it but the battery light doesn't work any more.

Edited February 11, 2017 by Daviewonder

[erbs 42 1 Cars]

one thing i found out on mine was the battery bulb wasn't put in properly there fore not working, unbeknown to me is when the light didn't work the alternator wont charge, or is this an isolated problem? as soon as i got the bulb

 

working,14 volts of my multi-meter on the battery showed that it is now charging.

[Anthony 1,003]

The alternator will charge with the bulb failed or the exciter wire disconnected, but you usually need to rev the engine high enough that the alternator self-excites, typically 3-4k rpm.

 

Can't remember wire guage off the top of my head Ali, but terminals are to suit M6 thread for shunt box and 8v/Mi16 alternator, and M8 for starter and GTi6 alternator. Length needed for shunt box is less than a foot.

[jackherer 543]

The standard wire gauge is tiny, I always overspec it to about twice what it was!

[GLPoomobile 958]

If rewiring, make sure you get decent new rubber boots for the ring terminals too. Crimping is a bastard unless you have the proper meaty bastard tool for doing it properly or go somehwere that can crimp them on for you properly.

[jackherer 543]

I bought one of these - http://www.ebay.co.uk/itm/361496998605 - it's made power leads for several cars now and is still as new.

 

I definitely agree about the rubber boots, there is no fuse on the main power lead so the boot is the only safety measure.

[welshpug 1,666]

that looks a great tool for the price, even if it doesn't last long you'll save a fair bit in making up your own leads.

 

 

I realise now that I fixed this problem myself way back when I did the Motronic conversion, I'd had the very faint glow on the cluster but thought nothing of it, so much so that I hadn't realised it had gone, when I went to do the first turn of the key after finishing the wiring I got nothing at all, dash lights went out and the starter made a quiet click.

 

fiddled about and the terminal to the shunt box snapped off in my hand!

 

 

this may also help many with the poor starter solenoid performance given ALL the vehicle electrics are fed through the shunt box bar the starter motor itself.

Edited February 12, 2017 by welshpug

[jackherer 543]

this may also help many with the poor starter solenoid performance given ALL the vehicle electrics are fed through the shunt box bar the starter motor itself.

It's too early to be sure but I think fitting the new power leads has solved an intermittent clicking starter on mine. And I already had a new starter and all new wiring to the solenoid so I was running out of things to change. It hasn't happened since I changed the power leads but if it returns I'm going to fit a new immobiliser.

[toolie72 67 1 Cars]

Must admit I have toyed in the past with the idea of putting dedicated alternator cable and dedicated starter cable as two leads just running beside each other-doing away with the join on starter

Lazy f@cker tho so I haven't convinced myself it would be worth the trouble (apart from when in petrol station getting clickclick aargh)

[jackherer 543]

I think that would just be redundant wire, I use a crimp on the starter that is able to take two heavy gauge cables so it replicates the original setup but with much thicker wire even from the alternator.

[GLPoomobile 958]

Thinking back to when I got my very first GTI the first thing I did was fit a K&N57i kit, and to do that meant removing the shunt box. I was young, naive and clueless and since the wiring wasn't long enough to secure the shunt box anywhere I left it dangling under the AFM supported only by the wiring itself. I've a feeling my Mi was the same when I bought it, and that was converted by a well regarded company I wonder how many others are similar. A recipe for disaster if the wiring suddenly breaks free!

[jackherer 543]

Now you say that I recall the wire snapping off the shunt box on my 205 a little while after installing a K&N in about 1999/2000! I don't think it was dangling but it had been moved which was the last straw for the ring connector. I stopped at a give way for a roundabout and the whole car turned off, I just wedged the remains of the terminal between the two studs on the end of the shunt box and drove home carefully.