Confusing altenator problem

Kwakerman · Jan 31, 2016

Just to throw a curved ball in. I know on later models (300 tdi) that there is a 100 ohm resistor in parallel with the warning light so that if the bulb blows the alternator will still excite and produce power. If that resistor is present in your car then my money (figuratively) is on the no power to the bulb argument. Will wait and see

The Mad Hat Man · Jan 31, 2016

Kwakerman said:
Just to throw a curved ball in. I know on later models (300 tdi) that there is a 100 ohm resistor in parallel with the warning light so that if the bulb blows the alternator will still excite and produce power. If that resistor is present in your car then my money (figuratively) is on the no power to the bulb argument. Will wait and see

its a hybrid.... - 1987 land rover 90 with disco 200 tdi

Kwakerman · Jan 31, 2016

The Mad Hat Man said:
its a hybrid.... - 1987 land rover 90 with disco 200 tdi

That's why I said 'If that resistor is present in your car'

toms3 · Feb 1, 2016

well i got a bit of testing done and I took out the plug going to the back of the dash lights and tested the plug contacts and theres no voltage going to tit and i put a new bulb in and no light or power going to it! whats the next thing I could check?

toms3 · Feb 1, 2016

with the multi meter on the battery and the engine running i am getting 12.6 volts at the battery, just to test i put a jump lead on the positive battery terminal and just touched the small (exiter?) wire and bingo, it changed noise and then i was getting 14+ volts at the battery!

toms3 · Feb 1, 2016

I have some spare wire and connectors what would you recommend to do to the repair this myself as I try to be as self sufficient as possible, thanks for the advice so far i wouldn't have had a clue where to Start otherwise! cheers

Tom.

The Mad Hat Man · Feb 1, 2016

when testing ALWAYS use a 5w bulb in the circuit.
use a spare ign live feed via 5w warning lamp to the thin wire terminal on the Alt.
should all work hunky dory then. looks like you have a problem getting volts to the warning lamp panel (broken track). any other warning lights not working?

toms3 · Feb 1, 2016

yes oil pressure not working either

thanks for that mad hat man i will also wire a 5w fuse in. where would you recommend getting an ignition live from?

cheers

tom.

The Mad Hat Man · Feb 1, 2016

toms3 said:
yes oil pressure not working either thanks for that mad hat man i will also wire a 5w fuse in. where would you recommend getting an ignition live from?

cheers

tom.

do NOT fit a fuse - just a 1.5w bulb. ignition live..... cigarette lighter?

toms3 · Feb 1, 2016

The Mad Hat Man said:
when testing ALWAYS use a 5w bulb in the circuit.
use a spare ign live feed via 5w warning lamp to the thin wire terminal on the Alt.
should all work hunky dory then. looks like you have a problem getting volts to the warning lamp panel (broken track). any other warning lights not working?

The Mad Hat Man said:
do NOT fit a fuse - just a 5w bulb. ignition live..... cigarette lighter?

Thank you, I think my cigarette lighter is permenant live as I can charge my phone ect with ignition off.

toms3 · Feb 1, 2016

could I repair it to work as it should do with original warning light?

jamesmartin · Feb 1, 2016

toms3 said:
could I repair it to work as it should do with original warning light?

warning lights should be fed by a white ignition live from fusebox originating at ignition switch a feed from there would fix the issue

The Mad Hat Man · Feb 1, 2016

original waring light is on the dash cluster. you would need to find the break in supply

Kwakerman · Feb 1, 2016

I also think that the standard warning lamp is only 1.2 watts. Best option is to sort it properly, if you can fix this you will probably fix the oil pressure warning at the same time which is arguably more important than the alternator warning, you could end up with a wrecked engine if you lost oil pressure for some reason!

toms3 · Feb 1, 2016

jamesmartin said:
warning lights should be fed by a white ignition live from fusebox originating at ignition switch a feed from there would fix the issue

Thank you for that. I can't wait to have a look at it tommorow!

toms3 · Feb 1, 2016

The Mad Hat Man said:
original waring light is on the dash cluster. you would need to find the break in supply

Would that be a cate of testing it at various points with the multi meter until I found it without any voltage?

toms3 · Feb 1, 2016

Kwakerman said:
I also think that the standard warning lamp is only 1.2 watts. Best option is to sort it properly, if you can fix this you will probably fix the oil pressure warning at the same time which is arguably more important than the alternator warning, you could end up with a wrecked engine if you lost oil pressure for some reason!

Yes this is my plan now too are the 2 linked to same white wire?

jamesmartin · Feb 1, 2016

toms3 said:
Yes this is my plan now too are the 2 linked to same white wire?

same source for both

The Mad Hat Man · Feb 1, 2016

Check the contacts, tracks and resistors ringed

Kwakerman · Feb 1, 2016

toms3 said:
Yes this is my plan now too are the 2 linked to same white wire?

Yes, I'll also take a guess that your diff lock light doesn't work either as that shares the same supply

Confusing altenator problem

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