Hi everyone

My GP is currently capable of running without the ignition being on!

Ignition relay is buzzing like hell when the battery is connected, and pulling the relay kills the engine. Have tried swapping the relay for a new one to no avail.

Issue started when I had a full loss of ignition and electric power on the road yesterday due to a loose battery terminal connection.

Anyone have any idea/experience of this?

Jack

As you've thought, first suspect would be faulty ignition relay, but this does not appear to be the case.
Next thought is that the relay is being closed by a feed across its switching terminals, normally provided by the body ECU. With the relay pulled, and ignition off, there should be no power across the switching terminals.
My guess is there will be power there.
Ignition switch on column could be shorting out inside, so get the cowling off and check.
From other posts, when the plenum chamber below the windscreen fills with rainwater, and the drains are blocked, the water overflows into the car, and onto the body ECU. So check its connector is dry. Also check and drain the plenum if necessary. There are two drains, short rubber tubes, that fill with dead leaves and become compost.

portland_bill said:

As you've thought, first suspect would be faulty ignition relay, but this does not appear to be the case.
Next thought is that the relay is being closed by a feed across its switching terminals, normally provided by the body ECU. With the relay pulled, and ignition off, there should be no power across the switching terminals.
My guess is there will be power there.
Ignition switch on column could be shorting out inside, so get the cowling off and check.
From other posts, when the plenum chamber below the windscreen fills with rainwater, and the drains are blocked, the water overflows into the car, and onto the body ECU. So check its connector is dry. Also check and drain the plenum if necessary. There are two drains, short rubber tubes, that fill with dead leaves and become compost.

Click to expand...

Thanks so much for your help! By switching terminals do you mean the metal connections in the relay ‘plug’ in the box?

I’d like to have a look at the terminals in the box anyway, would you know how to get into the fuse box itself? It feels like a fairly sealed unit..

Thanks again

Jack

"buzzing like hell", are you talking about T6 relay ??

BRs, Bernie

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JackGlendinning said:

Thanks so much for your help! By switching terminals do you mean the metal connections in the relay ‘plug’ in the box?

I’d like to have a look at the terminals in the box anyway, would you know how to get into the fuse box itself? It feels like a fairly sealed unit..

Thanks again

Jack

Click to expand...

A relay is just a heavy duty switch.

Two terminals are used to energise the switch, (the 'switching' terminals) See Bernie's diagram above, these should be terminals 85 & 86. There is usually a diagram on the relay itself, showing two terminals with a connection across the central part, usually a cylindrical shape, and the other two terminals are via a switch.

When current is passed across the switching terminals, the relay should be energised to close the switch, therefore making a circuit across the other two terminals. (87 & 30)

The connectors in the relay box should be a feed, into 85, live from the battery, and earthed through 86 by the ECU. There should be no continuity at 86 with the ignition off.
With the relay out, it can be checked for continuity, should (and will be in this case) have continuity between 85/86, but should be open between 87/30 unless energised. The relay is probably OK, although might have sustained damage by now.

Something is causing an earth path from 86, possibly a fault in the ECU, but less likely. More likely a short circuit under the fusebox. A common problem is water ingress, so make sure it is dry, and if necessary dry it thoroughly with a hairdryer. Don't use a hot air gun, you'll melt it. Then sort out how the water got in to prevent a recurrence.

Thanks to Portland_bill, those who did not knew before have certainly a better understanding of how a relay works and what's his purpose ...

BRs, Bernie