Flickering Ignition Light

D

DAV8

Member
Hi All,
My apologys for restarting this thread having read "Herbies" (Richard's) comments on 26th December 2012 regarding the flickering ignition light, so, Richard, have you solved the problem, i.e. was it the brushes in the alternator?, how difficult is it to replace the bushes?, I am asking these questions now because I have noticed recently on my 3500 auto an occaisonal flicker of the said light, everything else seems as it should be, so before I start exploring the electrical system your experience would be very helpful and of course anyone else that has the electrical knowhow.
My 3500 auto is a 1971 "J" reg so I think the alternator is a 11AC type, I have had a read at the workshop manual (the thick white one) and this gives possible causes, one being worn bushes, another being the Lucas 6RA control system relay, and one being the Lucas 3AW warning light control (this unit is similar to the flasher unit FL5 but the 3AW has a distinctive green label to avoid using the incorrect unit), does anybody know where the 3AW is situated?, I am fairly sure that all the exisiting units on the car are the originals except for the alternator which had a rebuild some years ago (this could be about 25 years!!) so, any help would be very much appreciated. Many Thanks

DAV8
Dave
 
Hi Dave. I have the 11ac alternator fitted to my 3500. My warning light was constantly flickering. I replaced the bushes and the control unit last year but the light was still flickering, until recently when the light just stayed on constantly. Last week before m.o.t time I cleaned up my fusebox and took the opportunity to look at the 3aw relay while I was on. I gave the contacts a clean but the main problem seemed to be earth contact. It had totally rusted over where the earth contacts the body shell. After giving that a damn good clean I've had no problem with the warning light or charging of the battery. It's located in the drivers knee bin/glove box by the way, on the right hand pillar below the bonnet release handle. Hope this helps?

Will
 
Hi Will, Thanks for your reply, I will have a look at the earth's has you suggest but I do try to keep on top of these but then again you never know.
Best Regards
Dave
 
^Well, I spoke to soon!^ The flipping thing is playing up, flickering constantly again!..and I was just saying to someone how the car was back in my "good books" :LOL:

I'm all out of ideas (nowt new there!) if anyone knows why it's doing this? Could a replacement 3aw sort it out?

Will
 
Hello again Will,
I think thats what you call "sods law", I have gone round checking all the earths, cleaning them and applying some petroleum jelly, as for the solenoids etc I have sprayed them with WD40, the flickering hasn't returned but I haven't had the chance to have a decent run, only travelled about 10 miles so, here's hoping.
Best Regards. Dave
DAV8
 
I had a flickering ignition light for a while too. It took me a while to solve but the instrument panel was shorting out on to the base unit when the car went over a bump. The instrument panel mounting brackets have oval holes so I moved it down slightly and now it doesn't flicker.
 
testrider said:
I had a flickering ignition light for a while too. It took me a while to solve but the instrument panel was shorting out on to the base unit when the car went over a bump. The instrument panel mounting brackets have oval holes so I moved it down slightly and now it doesn't flicker.
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How on earth did you figure that out? I would never in a million years have thought of that! :LOL: . That sounds like a good explanation as to what might be the problem with mine, as it seem to flicker more over bumpy surfaces. Cheers, I'll give that a try.

Will
 
Will, I'd had the whole lot out to work on the windscreeen surround and replace the dash top and got the flickering light afterwards, but the car had been in bits for 6 months so I didn't twig that it was the panel until some months later when the odometer broke and I had to take it to pieces again. During that time I drove it without the plastic cover on and the ignition light didn't flicker!

I knew there wasn't a charging problem because the ammeter was working as normal.
 
Hi Will,
Spoke too soon!, same here, I had a short run last Saturday and I had the flickering, had a longer run on Sunday (visiting family) about 20 miles, got the flickering, I don't think it was over the bumps etc, I came to a stand still and there it was for a few seconds, funny thing though on my way home over the 20 miles, absolutely nothing!!, a real head scratcher now, I might take the car to a local auto electrician where they do diagnostic checks, anybody else got any ideas?
DAV8
Dave
 
testrider said:
Will, I'd had the whole lot out to work on the windscreeen surround and replace the dash top and got the flickering light afterwards, but the car had been in bits for 6 months so I didn't twig that it was the panel until some months later when the odometer broke and I had to take it to pieces again. During that time I drove it without the plastic cover on and the ignition light didn't flicker!

I knew there wasn't a charging problem because the ammeter was working as normal.
Click to expand...

Well Paul, I had the instrument panel apart on Sunday to look at the clock which had stopped working. Managed to sort that out then adjusted the mounting position of the panel, as I was sure it was the same problem you had. Took the car for a drive and no flickering for about half a mile, then it started again..with a vengeance! :evil:

DAV8 said:
Hi Will,
Spoke too soon!, same here, I had a short run last Saturday and I had the flickering, had a longer run on Sunday (visiting family) about 20 miles, got the flickering, I don't think it was over the bumps etc, I came to a stand still and there it was for a few seconds, funny thing though on my way home over the 20 miles, absolutely nothing!!, a real head scratcher now, I might take the car to a local auto electrician where they do diagnostic checks, anybody else got any ideas?
DAV8
Dave
Click to expand...

I think most of us here know that "spoke too soon" feeling all too well Dave. If you do take it for a check I'd be very interested to hear the outcome.
So far I have replaced my alternator control box, the alternator brushes and the 3aw ignition warning unit to no avail. These were apparently n.o.s units, but I suppose anything of that age could potentially be faulty? Maybe I'm just worrying too much?, as to be fair the battery still seems to charge. The ammeter never shows a discharge with the engine running, the needle is always in the + side. One thing I have noticed though is that the needle doesn't stay still, rather it flicks into the + side of the gauge.

Will
 
Hi Will,
Yes I suppose we do tend to worry a bit, regarding the ammeter, I kept looking at it on my last outing, now normally the needle doesn't move much at all, stays right in the middle, after first starting the car it goes right into the + side, I have noticed when I have the headlights on and I'm stood the needle will go into the minus side but then move off and it will go into the + side, then level out, but as we say, perhaps we worry too much but then again I like to have things correct, so hopefully I will visit the auto electrician and get it sorted, I'll let you know. Regards
Dave
 
DAV8 wrote,...
now normally the needle doesn't move much at all, stays right in the middle, after first starting the car it goes right into the + side, I have noticed when I have the headlights on and I'm stood the needle will go into the minus side but then move off and it will go into the + side, then level out, but as we say, perhaps we worry too much but then again I like to have things correct, so hopefully I will visit the auto electrician and get it sorted, I'll let you know.
Click to expand...

Hi Dave,

That is exactly what it is supposed to do. By the sound of what you have written above, your alternator is now working as it should.

Ron.
 
Hi Ron,
Thanks for the info, could it be possible that it's put itself right?, I was just wondering! has anybody actually come to a stand still (okay! broke down, don't like using the term "broke down" where Rovers are concerned!!) due to this situation?
Regards
Dave
 
Hi Dave,

Although I have no experience with the 11AC alternator and its associated parts, the principal is the same as the 18ACR. Provided your ammeter does not show a discharge (-ve) at the same time as the ign light is on whilst driving. Anything much above idle and the ign light should be off and the ammeter should be either resting over the zero or reading positive (+ve). If you have lights etc on at idle, then the ammeter will show a discharge (-ve) and this is normal.

With the 18ACR, worn brushes will cause the ign light to either flicker or stay on periodically whilst driving, but the ammeter will also follow suit and show a discharge whilst the light is on. A voltage regulator which is starting to misbehave can also promote the same symptoms.

You can do a simple test to see if your alternator is charging as it should. With the engine idling, measure the voltage across the battery. Using a digital multimeter is the most accurate means for this. The reading should be within the range of 13.6 through to say 14.3 Volts. Now switch on your high beams, radio and blower. Have an assistant raise the engine revs to 3000 whilst you measure the battery voltage. It should be at least 13.6 Volts.

Ron.
 
Hi Ron,
I have carried out the test as you suggested today, this is how it went, the car has been stood for a week, so I checked the battery first (with a multimeter) reading was 12.6, the car wouldn't start, charger on for about 10 minutes, checked the battery again this time a reading of 13.6! car started immediatly, ran him up to temperature, checked the reading at tickover, 13.8/14.0, rev up to 3000, lights, blower on etc gave a reading of 14.4/14.6! what do you think?
Best Regards, Dave
DAV8
 
Hi Dave,

Well the alternator is certainly charging all right so it would appear. Hopefully it will provide reliable service for your Rover for quite a while. :)

Ron.
 
Hi Ron,
Many thanks for all the info, perhaps the "Organ Doctor" may have a point with a new battery, the one thats on the car now has been there for 11 years plus.
Best regards Dave
DAV8
 
Hi All,
The flickering Ignition light!, I think I may have solved this problem at least on my 1971 V8, I bought a new 3AW unit from a company in North Wales (e-mail automarineelectrical@gmail.com, phone 07934 653355), so far I have driven about 100 miles and no flickering light, so here's hoping. Hope this helps anyone with the same problem.
DAV8
Dave
 
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