Glowplug wiring question

Obi_110 · Sep 30, 2023

Morning all,

My 110 started life with a V8, however it is now running a discovery 200tdi (all done by one of the POs).

I've just finished the top-end rebuild, and have fitted new glowplugs and have a new glowplug relay, however, as the glowplugs haven't been wired in before, I don't have any previous wiring to follow.

Can someone either share a wiring diagram, or tell me how these need to be wired? Helpfully the relay didn't come with a diagram...

ALSO

The PO replaced the ignition, but it doesn't have the same point of resistance my previous defenders had where you can prime the glow plugs - is there a diesel ignition vs a petrol one, could my 110 still have a petrol ignition? Can I simply wire the glowplugs into a simple push button for now?

TIA

miktdish · Sep 30, 2023

Modern (ie after the SIII) 90's and Defenders deployed a glowplug relay that has a timer built in so you dont turn the key fully over and count to 10 any more ...

You give it power and the relay provides power to the glowplugs which automaticaly turns off after 15 seconds (ish).
You need to turn off and on again to get the power to the glowplugs.

Turboman · Sep 30, 2023

miktdish said:
Modern (ie after the SIII) 90's and Defenders deployed a glowplug relay that has a timer built in so you dont turn the key fully over and count to 10 any more ...

You give it power and the relay provides power to the glowplugs which automaticaly turns off after 15 seconds (ish).
You need to turn off and on again to get the power to the glowplugs.

I don't think Nineties and One Tens had that system, at leasst my 89 didn't, and that is a pretty late one.

On mine, you just turned the key up a bit, the light came on, and then you turned the key a bit further to start the engine.

The timer system came later on, although I don't know when.

Obi_110 · Sep 30, 2023

Turboman said:
I don't think Nineties and One Tens had that system, at leasst my 89 didn't, and that is a pretty late one.

On mine, you just turned the key up a bit, the light came on, and then you turned the key a bit further to start the engine.

The timer system came later on, although I don't know when.

Yeah, my 83 and 86 were the same, and you did have to count to 10

I'm just not sure with mine, as its a bit of a mongrel with v8 and discovery going on.

miktdish said:
Modern (ie after the SIII) 90's and Defenders deployed a glowplug relay that has a timer built in so you dont turn the key fully over and count to 10 any more ...

You give it power and the relay provides power to the glowplugs which automaticaly turns off after 15 seconds (ish).
You need to turn off and on again to get the power to the glowplugs.

I'll see if there's anything about the relay I have online, be handy if it is clever enough to time the output, I could possibly test on the bench once I know how to wire...

miktdish · Oct 1, 2023

Does yours look like this ?

Turboman · Oct 1, 2023

Obi_110 said:
Yeah, my 83 and 86 were the same, and you did have to count to 10

I'm just not sure with mine, as its a bit of a mongrel with v8 and discovery going on.

I'll see if there's anything about the relay I have online, be handy if it is clever enough to time the output, I could possibly test on the bench once I know how to wire...

Tdis are usually good starters anyway, you might not need the glow plugs. If you can get it to turn over and start, you could deal with them later.

I think you could probably get the ignition switch off a diesel One Ten, and fit that, and operate it like a 2.5 TD engined One Ten.

Obi_110 · Oct 1, 2023

miktdish said:
Does yours look like this ?
View attachment 299075

Er, pin position yes, numbers, no! Still safe to follow you reckon??

Obi_110 · Oct 1, 2023

Turboman said:
Tdis are usually good starters anyway, you might not need the glow plugs. If you can get it to turn over and start, you could deal with them later.

I think you could probably get the ignition switch off a diesel One Ten, and fit that, and operate it like a 2.5 TD engined One Ten.

Oh yeah, she spins over fine right now, just hoping to continue using through winter and not garage, so I suspect on cold mornings glow plugs will help no end

Turboman · Oct 1, 2023

Obi_110 said:
Oh yeah, she spins over fine right now, just hoping to continue using through winter and not garage, so I suspect on cold mornings glow plugs will help no end

My mate has had a couple of 200 Tdi Defenders. he lives in Kernow, but quite high up, about 600 feet, I should think.

I don't think he ever used the glow plugs at all.

lynall · Oct 1, 2023

Tbh any relay man enough will do the job, no need for a timer.
200 will start with no glow plugs, but life is much easier during winter if they work.

landowner · Oct 1, 2023

Ran my 200tdi for years with no glow plugs, started every time in winter just took 3 seconds instead of 1.5 seconds

Turboman · Oct 1, 2023

landowner said:
Ran my 200tdi for years with no glow plugs, started every time in winter just took 3 seconds instead of 1.5 seconds

Compression must have been down a bit without the plugs in, too!

Hicap phill · Oct 1, 2023

I just have a big relay I count to 10 if there is snow or frost on the screen.
I don’t use the motor weekly/daily so want it to start when needed.

miktdish · Oct 1, 2023

Obi_110 said:
Er, pin position yes, numbers, no! Still safe to follow you reckon??

View attachment 299111

Yes I think so. The large connectors are the feed to the glowplugs.
The others are a live feed and a feed to energise the timer, the timer closes the connection between the 2 big spades and will also put a voltage on the 'indicator' pin.
You will feel a click as it energises and a click when it lets go (about 10 to 15 seconds).

Obi_110 · Oct 1, 2023

miktdish said:
Yes I think so. The large connectors are the feed to the glowplugs.
The others are a live feed and a feed to energise the timer, the timer closes the connection between the 2 big spades and will also put a voltage on the 'indicator' pin.
You will feel a click as it energises and a click when it lets go (about 10 to 15 seconds).

Thanks so much, I'll jury rig something up outside the vehicle to test!

Obi_110 · Nov 1, 2023

miktdish said:
Does yours look like this ?
View attachment 299075

Sorry to dredge up an old post - Thanks for the help with this - I've managed to mock the relay in situ, but I'm struggling to get my head around how to wire in 3 & 5 - I assume they can be used to provide an indicator light that the relay is active, then is powered down.

So far, I have:

1) constant power in from battery
2) "glow plug" (AKA a lightbulb atm on my bench set up) that earths out back to neg
3) ?
4) Live from ignition
5) ?
6) Earth back to neg

Energising the relay with (4), the relay is active for about 17 seconds then clicks off, but I'm not seeing power to either 3 or 5 during that time - duff relay, or am I doing something wrong?

TIA

FlyingPete · Nov 2, 2023

Pin 3 is an input which connects to the starter motor solenoid- the idea being that if you leave the ignition on and the relay times out, it will energise the glow plugs again when you crank the engine.

Pin 5 is for the switched output for the warning light on the dash- on older models this simply used the same indicator as the choke on a petrol. I can't remember if this provides a switched positive or a switched ground. It may be the latter, in which case you put an ignition-switched 12v to one side of the choke warning lamp, and the other side earths via the relay.

Obi_110 · Nov 2, 2023

FlyingPete said:
Pin 3 is an input which connects to the starter motor solenoid- the idea being that if you leave the ignition on and the relay times out, it will energise the glow plugs again when you crank the engine.

Pin 5 is for the switched output for the warning light on the dash- on older models this simply used the same indicator as the choke on a petrol. I can't remember if this provides a switched positive or a switched ground. It may be the latter, in which case you put an ignition-switched 12v to one side of the choke warning lamp, and the other side earths via the relay.

Ah, thanks for that, I'd not thought of it being a switched earth, I'll give that a try!

Glowplug wiring question

Obi_110

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miktdish

Guns n Chainsaws

Turboman

Mab An Gov

Obi_110

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miktdish

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Turboman

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Obi_110

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Obi_110

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Turboman

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lynall

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landowner

Pensioner Pete

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Hicap phill

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miktdish

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Obi_110

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FlyingPete

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Obi_110

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