Disco 1 S terminal

currymunster · Oct 16, 2020

Hi everyone,
Discovery 1 300tdi 1995
Having just completely stripping and rebuilding my A127i-100 alternator I notice the regulator on old and new head an S terminal.
Does anyone know why land rover did not use it and is it worth running a cable to the battery for it?
Just wondering

discool · Oct 17, 2020

They possibly did... but only on vehicles fitted with an external regulator, as the alternator has built in regulator the S terminal is redundant when fitted to a discovery 1.

currymunster · Oct 17, 2020

discool said:
They possibly did... but only on vehicles fitted with an external regulator, as the alternator has built in regulator the S terminal is redundant when fitted to a discovery 1.

Mine is an A127i which has the internal regulator. The S terminal is on the regulator and the plastic rear cover has S marked for it and a push out blanking cover for it.
I just wondered why it was redundant on the discovery 1 and if it could be used if I ran a wire from it to the battery positive terminal. Hopefully it would read the voltage drop and adjust the voltage accordingly?

discool · Oct 17, 2020

As u state the alternator u have already has a voltage regular, the alternator you have wasn’t fitted when your disco left the factory.
If you wish to know more about the S termInal or how a regulator functions... Google

currymunster · Oct 18, 2020

My alternator is dated 95 when the car was built and head land rover printed on it along with a part number. What makes you say it wasn't the one I've was built with?
I already know what the sense terminal is I just wondered why it wasn't used as it is quite an important feature.

currymunster · Oct 18, 2020

discool said:
As u state the alternator u have already has a voltage regular, the alternator you have wasn’t fitted when your disco left the factory.
If you wish to know more about the S termInal or how a regulator functions... Google

Out of curiosity mate. While I was pottering I found a broken wire which judging by the green head been broken for a while. It comes straight of the battery and is quite thick. It's brown and orange.
Do you have any clue what is for?

discool · Oct 19, 2020

currymunster said:
My alternator is dated 95 when the car was built and head land rover printed on it along with a part number. What makes you say it wasn't the one I've was built with?
I already know what the sense terminal is I just wondered why it wasn't used as it is quite an important feature.

Well with the A127i 100w for the D1 From my quick search in the parts book I can give u at least four different part numbers for an alternator for the 300 series disco, also the LR wiring diagram fro the alternator shows the three wires, 1. battery, 2. warning lamp and 3. rev counter.

sierrafery · Oct 19, 2020

currymunster said:
It comes straight of the battery and is quite thick. It's brown and orange.

A thick brown/orange wire goes to the glow plug timer relay's contact, if it's interrupted the glow plugs will get no feed

currymunster · Oct 21, 2020

discool said:
Well with the A127i 100w for the D1 From my quick search in the parts book I can give u at least four different part numbers for an alternator for the 300 series disco, also the LR wiring diagram fro the alternator shows the three wires, 1. battery, 2. warning lamp and 3. rev counter.

That's great. Thank you.

currymunster · Oct 21, 2020

sierrafery said:
A thick brown/orange wire goes to the glow plug timer relay's contact, if it's interrupted the glow plugs will get no feed

Thanks. I'm spent ages looking through the wiring diagrams but couldn't find it.
My car has had a lot of people... Shall we say, adjust things over the years.
So now time to see if the wire is still used for the glow plugs. It may have had another mod to compensate.
Although judging by the blue electrical tape around the bad repair is say it probably now means my glow plugs have no feed.
Many thanks

currymunster · Oct 26, 2020

sierrafery said:
A thick brown/orange wire goes to the glow plug timer relay's contact, if it's interrupted the glow plugs will get no feed

Might be a silly question but here goes.
The glow plug feed cable is broken about 3 inches from the battery.
I assume a join will be okay.
I was going to do a crimp.
It looks like 6mm² wire.
Where does the other end go to... Would it be viable to replace the whole run to the relay?

sierrafery · Oct 26, 2020

currymunster said:
Would it be viable to replace the whole run to the relay?

That would be the best IMO

discool · Oct 26, 2020

I

currymunster said:
Might be a silly question but here goes.
The glow plug feed cable is broken about 3 inches from the battery.
I assume a join will be okay.
I was going to do a crimp.
It looks like 6mm² wire.
Where does the other end go to... Would it be viable to replace the whole run to the relay?

If your replacing the feed to the glow plug relay/timer entirely then don’t forget to replace the fusible link, or reuse the existing one if u still have it, also sleeve the the length wire for additional protection.

currymunster · Oct 27, 2020

sierrafery said:
That would be the best IMO

discool said:
I

If your replacing the feed to the glow plug relay/timer entirely then don’t forget to replace the fusible link, or reuse the existing one if u still have it, also sleeve the the length wire for additional protection.

I had a quick look and found the relay on the back of the engine fuse box.
Not even half a metre of wire needed.
Can't find any fuse in the wire though.
Maybe that's why my wire is joined and now broken.
Wire of battery is brown. Then from break in wire it's brown with an orange tracer.
I see though that the relay has a factory plug. Will I be able to remove the old wire and fix a new one in?
Also is a 60amp fuse okay?

discool · Oct 28, 2020

currymunster said:
I had a quick look and found the relay on the back of the engine fuse box.
Not even half a metre of wire needed.
Can't find any fuse in the wire though.
Maybe that's why my wire is joined and now broken.
Wire of battery is brown. Then from break in wire it's brown with an orange tracer.
I see though that the relay has a factory plug. Will I be able to remove the old wire and fix a new one in?
Also is a 60amp fuse okay?

Yes 60amp is the factory fit rating for the fuse and possibly was fitted just a few inches from the battery, (don’t know what it looks like, i don’t have one) but i’d go for a fuse holder of the weatherproof type as its at the front of the vehicle... would it be that its just the fuse holder is missing? If so u just need u just need to fit it to the brown/orange and replace the brown wire to reach the battery if to short to reach the new fuse.

Or, If your installing a new wire to the relay removing the female spade terminal from the socket, may be easy to pull out, then remove the old wire and crimp and solder replacement wire, refit terminal. If not then leave the terminal in place and make a soldered joint and protect it outside the socket... thats unless u have a new female terminal handy to replace the existing one.

currymunster · Oct 29, 2020

discool said:
Yes 60amp is the factory fit rating for the fuse and possibly was fitted just a few inches from the battery, (don’t know what it looks like, i don’t have one) but i’d go for a fuse holder of the weatherproof type as its at the front of the vehicle... would it be that its just the fuse holder is missing? If so u just need u just need to fit it to the brown/orange and replace the brown wire to reach the battery if to short to reach the new fuse.

Or, If your installing a new wire to the relay removing the female spade terminal from the socket, may be easy to pull out, then remove the old wire and crimp and solder replacement wire, refit terminal. If not then leave the terminal in place and make a soldered joint and protect it outside the socket... thats unless u have a new female terminal handy to replace the existing one.

Yes, I think you are right. The original fuse is missing and a bad repair was done without it.
The wire had corroded badly unseen as it had been hidden in a fabric sleeve.
This corrosion head made the wire a bit short.
Besides, I've snipped it up to the battery and I wasn't happy having a live wire bouncing around in there.
I've got a battery terminal crimping tool so it's just about finding the terminals, wire and fuse. Think I've found most of it.

discool · Oct 29, 2020

Splash proof fuse holders something like this.
https://www.ebay.co.uk/itm/281667828154
https://www.ebay.co.uk/itm/132532370973

currymunster · Oct 29, 2020

Yeah, that bottom fuse is the one I quite fancied myself already.
Just need to measure the bolt on the battery terminal so I can get the correct crimp.
Also I remember looking at the engine fuse box and seeing air conditioning with a fuse. Wondered if that might be spare as I don't have air conditioning.
If so I could use that. Changing it to the correct rating of need be.

discool · Oct 29, 2020

That 60 amp circuit with a fusible link is still required for the heater blower even though the AC isn’t part of the heating system.

currymunster · Oct 29, 2020

discool said:
That 60 amp circuit with a fusible link is still required for the heater blower even though the AC isn’t part of the heating system.

There's a surprise. I thought it would be something like that. Thanks though, you've saved me a few minutes looking

Disco 1 S terminal

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