Ignition Light stays on

[GregT]

I'm making the most of my membership this weekend... :-)

I KNOW there's no logical reason to mention this, but yesterday I replaced the Brake/Rear light bulb (offside) on my car - all straightforward. But in the wild extremes that it might be relevant...

Went for a shortish drive after the bulb fitting and at some point noticed the Ignition light was staying on. No revving of the engine or speed changes made any difference. Left the car in the garage for a while and started up again - same issue. The battery terminals are clamped onto tightly, the fan belts both taut and spinning well.

Does this mean the alternator is the culprit, or is there anything else to check? Not sure how old it is or if it's been replaced by previous owners (need to go through the files) - Suggestions anyone? Cost of a replacement isn't huge (about £80.00). How much of a pain is fitting?

Thanks in anticipation....

Greg

[flying farmer]

Its normally the alternator, if you look at your voltmeter it probably reads under 12V when running. Sometimes its the brushes worn out, or its the voltage regulator or diodes.

Ease of replacement largly depends on which way round the long bolt the alternator pivots on has been fitted. If it has been pushed in from the front you will have to remove the radiator or saw the bolt into segments to get it out. Make sure the new bolt is fitted from the rear.

Neil

[GregT]

Thanks Neil - oh God I hope the last paragraph isn't the case...

There was a problem with the voltage levels and the battery was being depleted, but that was fixed a while back and it's been steady around 13-13.5 but yesterday it dropped as you say to about 10.5 or 11.0v.

It's not a job (replacement) that I'll try myself - just wondered if anything else should be checked and if it was to be replaced how long a job it is. To be honest if brushes being changed might fix it, as example, I'd rather put a new alternator in for peace of mind and to save another failure in near future for sonething else.

[StagJonno]

Agree with Neil but just checking - have you by any chance changed the warning cluster bulbs to LEDs? An LED in the ignition position can cause problems as it doesn't pass enough current to initially excite the alternator. If this is the case, then changing the Ignition bulb back to an incandescent (filament) type can rectify the problem. a

I find occasionally with my car that the Ignition light stays on until I've revved the engine to 2,500 - 3,000 rpm, but I'm guessing that you will have reached such levels when out driving.

If you have access to a decent auto-electrician, (bit rare these days) it could be worth seeking their assistance. If your alternator is otherwise sound, a service/ repair could be the best way forward. From what I've heard, some of the new alternators are of dubious build quality. Recommend checking out Robsport, LD Part, James Paddock for best quality new.

[GregT]

I had the dash bulbs changed to LED recently and all was fine. But it's worth checking out before spending £80 plus fitting.. Only thing is as Neil pointed out the voltage level is down and I would have doubted that the performance of the bulb would lower the charge levels?

Thanks for the idea though.

[StagJonno]

I think you misunderstand and if the Ignition bulb was changed for an LED, that is likely the cause of your problem.

Sometimes, there is residual magnetism on the rotor (field) which provides the initial excitation (following starting the engine) that allows the alternator to do its job. However, if this residual magnetism is lost (random probability), it relies on the current flowing through the incandescent ignition bulb to provide this. An LED will not pass enough current to perform this function.and therefore the alternator will not provide charge. Once initial excitation is provided, the regulator (either built into the alternator or as a separate module mounted on the RHS suspension tower) manages the charge current.

Changing a warning cluster bulb will take ~15 min and cost an awful lot less than a new alternator (which might not work either if it doesn't have residual magnetism on the rotor!

[GregT]

"I think you misunderstand"

Very, very likely! I'd not have a clue as to the electrical processes that go on. My capability is to make a circuit and check there's + and - connections. And on a good day that there's an earth. I'm not a mechanic or electrician - at best a 'bloke who fiddles about with hope'...

You're quite right it's worth changing the LED back to a standard bulb (I assume from your suggestion it's OK to have a mix of bulbs in the warning light cluster). I hadn't understood that the bulb type would have an impact on the rate of charge on the voltage display. Strange that this isn't a more widely seen phenomenon or that the LED guys haven't a work around.

I think I can probably manage to change the bulb so will try that before anything else.

Once again the value of experience in the Stag fraternity is impressive! Thanks for clarifying.

[GregT]

If it's a 15 minute job should I assume one can pull the cluster out from the dash from the front - removing the dashboard looks to be more complicated..?

[DJT]

If it's a 15 minute job should I assume one can pull the cluster out from the dash from the front - removing the dashboard looks to be more complicated..?

No, you have to lower the instrument panel to the service position as described in the Repair Operations Manual 88.20.01, which really only takes a coupe of minutes. Then you can remove the plug from the back of the warning cluster and follow ROM 86.45.62.

[GregT]

I was looking in the Haynes manual that suggests a more difficult task.. 'release the instrument panel and pull it forward.' The method is given as'disconnect the vent hose from the heater outlet duct on driver's side. Remove the panel rheostat knob, undo four screws and lift forward..'
Which to this klutz sounds tricky... I'll go down and take a look..

I presume the bulbs aren't something I can get at Halfords - would be a Rimmer or other purchase?

[Goldstar]

The hose doesn’t need to come off in my experience there’s enough travel. Undo the Philips screws on the wooden dash around the clocks (4 screws I think from memory) and pull off the dimming rheostat knob. The whole wooden dash with the dials will now move towards you. I also put the steering column down to its lowest point. Now just twist the retaining ring off the back of the cluster and undo the wiring and it will come out. Reassembly is the reverse as they say. If you don’t have a lamp I imagine you need to get one from a specialist or send your address in a pm and I’ll see if I have one

[GregT]

That's what I hoped someone would say! I assume the manual is written with the view of complete removal and replacement, but inevitably there are short cuts. I have access to another Stag from which I could borrow a bulb, assuming that the lights on that haven't been changed to LED (which they might have been). But thank you for the kind offer. Right, off to the garage - wish me luck! - Is the Repair manual on line somewhere in the SOC site? I don't have a copy, only the Haines Manual. Can't initially find any links to an online reference?

[DJT]

You can download a copy of the early one here: http://www.grampianstags.net/Stag%20...n%20Manual.pdf

The sections I referred to above say exactly what Goldstar has said in post 11. Heater hose does not need to be disconnected. The manual suggests lowering the steering column to its lowest setting to give more room.

[Goldstar]

Feel free to give me a shout if you get stuck, I’ll pm you my number.

[GregT]

Well for once, my forays into DIY maintenance went as you all described. I'll be having the gearbox out next... I now have the cluster on the desk beside me and have removed the ignition bulb. As you may have gathered I am not the most technically gifted, but the Ignition bulb looks to me like an incandescent bulb compared to the other LEDs. I've done the best I can to photograph the bulb under a magnifying glass. So it could be that Classic Dreamworks who fitted the LEDs for me along with the new dashboard were aware of the issue of LEDs on the IGN lamp. The Handbrake light bulb is similar. Whereas the other lamps are round bulbous style.