What is this relay for?

Well, I am having problems with my Disco starting, not the usual 'it won't start' but it can't help starting - as soon as ignition gets to stage 2, it starts to fire, and doesn't stop even when running.

So I am guessing its a component failing, and am guessing something simple like a relay.

I have found this one in the bonnet:-





When I disconnect it, I still have the disco trying to start, but I noticed that this stops the glow plugs working, so maybe this is at fault, given the amount of wires going into it, and the fact this relay has a microchip in it, but also clasping at straws too as I have noticed that as soon as I have the ignition on, the glow plug light goes straight out, given its trying to start.

I have ruled out the starter motor as this works fine with as 12v live feed to it, and also the whole ignition switch that is bolted onto the steering column as I replaced that for a new one yesterday.

See my earlier thread:

http://www.landyzone.co.uk/lz/f8/its-starting-itself-help-please-126774.html

I have temp fixed the problem by taking off the live feed to the starter, and running a separate 12v feed to it with a push switch fitted on the dash. Then on the cold mornings, I put the gear lever into 'D' which then lets the glow plugs time out, then back into 'P', press the starter button, and away we go - its works but not the best senario.....

Really, I could do with a wiring diagram of where the live feed that starts the starter motor goes to, in order to trace back to see what might be knackered.....

Cheers anyway for any input people may have.

It's the glowplug timer relay.......just google out PRC6193 and see more

Thanks for that - guess I can cross that one off my list - so now need to find the actual relay that feeds the starter motor - any pointers or pics anyone?

Are u sure is not the ignition switch letting contact on for ignition on position 2 ?

sure, as I have even cut the white and red wire feed from the ignition switch to the car, and it still wants to start

Sorry, i've just read your other thread....i dunno what type of starter has the Disco 1 but if it's similar with Disco 2 then the only thing i can think of is that the starter solenoid(which is part of the starter assy) it's blocked closed and it's feeding the starter motor permanently.

Don't think it can be that, as the starter solenoid is the bit on top of the starter motor (I think), that has the 12v live feed to it, and if this is removed, the starter stops, 12v applied, and it turns over, so it seems to be working as it should.

So I am thinking it must be something prior, as the 12v feed it always live as soon as you get to stage 2 of the ignition, and not stage 3 as it should be.

StuRox said:

Don't think it can be that, as the starter solenoid is the bit on top of the starter motor (I think), that has the 12v live feed to it, and if this is removed, the starter stops, 12v applied, and it turns over, so it seems to be working as it should.

So I am thinking it must be something prior, as the 12v feed it always live as soon as you get to stage 2 of the ignition, and not stage 3 as it should be.

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No m8 ...that's the problem, this solenoid has the live feed as it should but when it gets ignition feed(at the smaller contact of it) it must close the live feed circuit to the motor...... if u disconnect the "exciter" coil of the solenoid and the starter motor still turns it's deffinetly the solenoid blocked.

To understand: K4 is starter relay, M1 is the starter motor(+solenoid) ....dont bother with A162 its a feed for immobiliser controll module. As u can see there are 2 feeds on the starter, SW for the ("exciter")solenoid coil(this must bethe smaller/thinner on the solenoid) and rt the permanent one.......so if the solenoid doesnt get feed the permanent + doesnt reach the motor's coil either....so that contact (drawn inside the motor) must be open when the solenoid doesnt get feed that's why if u disconnect the wire(not the permanent one) from the solenoid the motor must rest.

I hope this helps

Nope, not that, have now fixed the problem, and it was a knackered relay behind the kick panel of the drivers side - guessing the relay from the main fuse box.

Switched the relay and jobs a good one.

Tested the old relay and there is a circuit between the 2 pins when they shouldn't be.

Well, here is the culprit that was causing me all the problems with the disco auto starting:-





You can see that the connectors and block are pretty corroded to say the least.

Also when I tested the relay, there is still a circuit across the to pins when it should be completely closed, so hence the disco trying to start all the time.

After a search on the internet I found that there were more relays behind the kickplate of the drivers foot well.

So pulled it off last night, and located the worst looking relay, pulled it out, and the glow plug light stayed on for its warm up, and no trying to start instantly – result.

Found a relay in my garage – a 30/40A one which I put in its place, and it would only start with a bit of wiggling, so I snipped off the connector block, and put new spade connectors on the wires, connected back up, and starts perfectly.

So my next question is, is there anyway of finding out what amp relay the knackered one is, to make sure the one I have put in will last?

I'm glad u sorted it out, it's 30A >> eBay.ie: Relay Siemens Yellow Range Rover Classic YWB10027 (item 350180733784 end time 11-Nov-10 06:21:53 GMT)

sierrafery said:

I'm glad u sorted it out, it's 30A >> eBay.ie: Relay Siemens Yellow Range Rover Classic YWB10027 (item 350180733784 end time 11-Nov-10 06:21:53 GMT)

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Cool, thanks for that - looks like the relay I have fitted will do the job just fine.