Ignition light resistor

Hi there guys, I have a 1988 Landrover 90. The ignition light came on recently while driving, but the alternator is charging just fine. A friend came to try to find the problem with me, and his conclusion is that the ignition light resistor has gone 'open circuit', which apparently in layman's terms means that it's bust!

Can anyone tell me where to find this resistor? We checked behind the dash and next to the warning lights, but couldn't find it.

Thanks
Rob

there is no resistor.
12volts is supplied to one side of the bulb and the other side is connected to the alternator. with the alternator not charging then the bulb is grounded by the alternator and the light comes on. As soon as the alternator starts charging, 12volts is output from the Alternator which means that there is 0volts across the bulb and it goes out.

Check the wires for it, check they aint chafing on something.
Check you alternator properly, at an auto electricians.

That's odd because we checked the voltage between the bulb and the positive terminal of the battery. With the ignition switched off this was -12.5v. Then when I started up, this changed to +4v. The explanation that this guy gave me was the while the engine was off, the alternator wasn't generating anything and therefore the 12v difference between the bulb and the battery. With the engine running, the alternator was generating more voltage than the battery and therefore the positive voltage. He said that the idea was that the ignition light resistor was designed to cap this positive voltage to keep it as close to zero as possible, and hence keep the light out.

Does any of that make any sense to anyone?

The wiring diagram that I have mentions an ignition light resistor, but it is a fairly generic diagram for all Landrover 90 models that I got on a DVD work manual.

My original problem was that the ignition light stays on after the engine is started. Very faint at tick over and gets brighter as the revs increase, but the voltage at the battery indicates that the alternator is definitly charging the battery. Any ideas?

Cheers
Rob

Dodgy connection somewhere between the light and the alt.

+4 volts over battery voltage is too high - sounds like the regulator is fooked, which is why the light is coming on when you rev the engine.

What voltage are you seeing at the battery? Should be no more than 14.7v, ever. If it is, then your regulator is indeed fooked and you are also cooking the battery.

Yes I'm mystified by this +4v between the bulb and the battery because if I measure between the positive and negative terminals of the battery I see 12.5 with engine switched off, and 13.8 with engine running, which seems about right.

Where would I find the regulator?

hello all. just got to say i'm new here so be kind.....
i've just finnished wiring up my landy dash and there is a resistor
it's buried behind alll the wires behind the dash up against the bulkhead. theres what looks like a fuse holder one side has a brown yellow wire to it and the other side a white wire. if you open the fuse holder the resistor even looks like a standard type barrel fuse
well mine has any way.
sorry if i'm wrong?

so whats yer question ?

sorry take the quetion mark off.
just trying to help RobNew with his question.

does it have heatsink on it? That sounds like the glow plug resistor if it is, mine dnt have one of those.

I could be wrong though.

If you are getting 13.8 v at the battery, then i think it point back to a poor connection somewhere from the light.

The regulator is in the back of the alternator also.

Thanks for all the suggestions guys, I will try to take a look at the weekend and see if I can work out what's up.

Cheers
Rob

Looking at my Haynes diagram (for diesels - although this shouldn't be different) there is a resistor, and if it failed it would cause the 'no charge' bulb to light. My dash is all over the place at the moment, so I'll have a look for mine (diesel but same age), and if I find it I'll be able to give a possible location. Tomorrow. It's too cold out there.