Disco 2 TD5 HRW blowing fuses

Andy Warren · Nov 4, 2021

Hi all, I've noticed today when I went to use the heated rear window/mirrors for demisting that they didn't work (the orange tell tail light in the switch illuminates). I checked the 30A & it had blown so replaced it started it up, switched the HRW on & it blew it straight away. I disconnected the mirrors, the two wires to the heated rear screen & removed the relay in the passenger fuse comp. replaced the fuse & the same thing happened.
Can the switch cause this or am I looking at a direct short some where (or worse the IDM)?
It's a 2001 ES premium with no other electrical problems & no additions to the wiring. The only thing I can't find any reference to is the heated side windows in the boot area, I presume these operate off the HRW switch, if so I'll look to isolate them for elimination purposes.
As ever any advice is much appreciated.

PopPops · Nov 4, 2021

Andy Warren said:
Hi all, I've noticed today when I went to use the heated rear window/mirrors for demisting that they didn't work (the orange tell tail light in the switch illuminates). I checked the 30A & it had blown so replaced it started it up, switched the HRW on & it blew it straight away. I disconnected the mirrors, the two wires to the heated rear screen & removed the relay in the passenger fuse comp. replaced the fuse & the same thing happened.
Can the switch cause this or am I looking at a direct short some where (or worse the IDM)?
It's a 2001 ES premium with no other electrical problems & no additions to the wiring. The only thing I can't find any reference to is the heated side windows in the boot area, I presume these operate off the HRW switch, if so I'll look to isolate them for elimination purposes.
As ever any advice is much appreciated.

Looking at the circuit diagram, the switch only talks to the BCU, not directly to the IDM, so it wouldn't cause this fuse blowing itself. I assume you are talking about F8. F8 only feeds the HRW relay (as far as I can see anyway) which then feeds the HRW and mirrors. It is unlikely to be the IDM (but could be, has it been water damaged?), most likely a short somewhere on the thick brown/purple cable from pin 4 on CO582. My guess would be where it gets movement from the doors and has maybe chafed, but I suppose anywhere it could have been damaged! Not much help and I don't envy you tracing through that!

PP

Stanleysteamer · Nov 4, 2021

Andy Warren said:
Hi all, I've noticed today when I went to use the heated rear window/mirrors for demisting that they didn't work (the orange tell tail light in the switch illuminates). I checked the 30A & it had blown so replaced it started it up, switched the HRW on & it blew it straight away. I disconnected the mirrors, the two wires to the heated rear screen & removed the relay in the passenger fuse comp. replaced the fuse & the same thing happened.
Can the switch cause this or am I looking at a direct short some where (or worse the IDM)?
It's a 2001 ES premium with no other electrical problems & no additions to the wiring. The only thing I can't find any reference to is the heated side windows in the boot area, I presume these operate off the HRW switch, if so I'll look to isolate them for elimination purposes.
As ever any advice is much appreciated.

Heated SIDE windows? They sure must have everything on an ES. Mine has a radio antenna in one and feck all in the other. now wondering where your radio antenna is.

Stanleysteamer · Nov 4, 2021

PopPops said:
Looking at the circuit diagram, the switch only talks to the BCU, not directly to the IDM, so it wouldn't cause this fuse blowing itself. I assume you are talking about F8. F8 only feeds the HRW relay (as far as I can see anyway) which then feeds the HRW and mirrors. It is unlikely to be the IDM (but could be, has it been water damaged?), most likely a short somewhere on the thick brown/purple cable from pin 4 on CO582. My guess would be where it gets movement from the doors and has maybe chafed, but I suppose anywhere it could have been damaged! Not much help and I don't envy you tracing through that!

PP

concur on chafing where the door opens and closes.

Andy Warren · Nov 4, 2021

Stanleysteamer said:
Heated SIDE windows? They sure must have everything on an ES. Mine has a radio antenna in one and feck all in the other. now wondering where your radio antenna is.

What a plank I am of course they're the radio aerials

. Well that's one less thing to check

. Like you not the best with electrickery but I'll start unplugging the door looms & checking the live supplies for shorts. I find it strange that even with the relay out it still blows so maybe it's between the 'battery' & the fuse box (where the HRW relay is). Thanks Stan.

PopPops · Nov 4, 2021

Andy Warren said:
What a plank I am of course they're the radio aerials . Well that's one less thing to check. Like you not the best with electrickery but I'll start unplugging the door looms & checking the live supplies for shorts. I find it strange that even with the relay out it still blows so maybe it's between the 'battery' & the fuse box (where the HRW relay is). Thanks Stan.

Which relay are you removing? As far as I can see, the IDM doesn't have a removable relay in the HRW circuit, the relay is one soldered to the board, which could be faulty in some way, water damage leaking to a nearby ground perhaps as the relay has no ground itself, is all I can see from the diagram.

I did wonder about the heated side windows, I assumed that it was the radio aerial on my Landmark!

Good luck!

Andy Warren · Nov 4, 2021

PopPops said:
Looking at the circuit diagram, the switch only talks to the BCU, not directly to the IDM, so it wouldn't cause this fuse blowing itself. I assume you are talking about F8. F8 only feeds the HRW relay (as far as I can see anyway) which then feeds the HRW and mirrors. It is unlikely to be the IDM (but could be, has it been water damaged?), most likely a short somewhere on the thick brown/purple cable from pin 4 on CO582. My guess would be where it gets movement from the doors and has maybe chafed, but I suppose anywhere it could have been damaged! Not much help and I don't envy you tracing through that!

PP

Thanks for that, yeah it's F8 that's blowing, as I just said to Stanleysteamer I guess it must be between the 'battery' + & the fuse box as it still blows with the relay out.
The sunroofs leaked when I got it in June 20 so I removed them & resealed + fitted a new fr. sunroof motor as it was seized solid due to water ingress. As I didn't put it OTR until this June I have no way of knowing when the fault occurred as it's the first time I've had to use the HRW (the front HS works fine as does everything else electrical). So it's out with the multimeter

.

Andy Warren · Nov 4, 2021

PopPops said:
Which relay are you removing? As far as I can see, the IDM doesn't have a removable relay in the HRW circuit, the relay is one soldered to the board, which could be faulty in some way, water damage leaking to a nearby ground perhaps as the relay has no ground itself, is all I can see from the diagram.

I did wonder about the heated side windows, I assumed that it was the radio aerial on my Landmark!

Good luck!

The fuse box has a removable yellow relay which I'm sure had heated rw embossed in the plastic of the FB & below that an empty relay slot which I believe is for the V8 petrol ign. coils. I'll take a pic as soon as SWMBO gets back with it.

PopPops · Nov 4, 2021

Andy Warren said:
The fuse box has a removable yellow relay which I'm sure had heated rw embossed in the plastic of the FB & below that an empty relay slot which I believe is for the V8 petrol ign. coils. I'll take a pic as soon as SWMBO gets back with it.

I assume we are talking about the passenger fuse box (IDM) because that one doesn't have a relay associated with the HRW and the engine compartment only has a fuse (FL6) associated with the HRW. The engine fuse box has a heated front screen relay, R8, but I think you are right, you need the car back from SWMBO!!

Andy Warren · Nov 4, 2021

Here's a pic of the fuse internal FB with & w/o the relay, it doesn't say heated by the relay as I thought !

discool · Nov 4, 2021

If you don't have the disco 2 fuse box details, then here it is.

Andy Warren · Nov 4, 2021

As mine blows F8 without the relay in am I right in thinking it would likely be between C0578-5 & C0584-5 ? HRW relay circled in blue & wiring to check *d2_electricalcircuitdiagrams_2000.pdf circled in red,hopefully.

Andy Warren · Nov 4, 2021

Sorry I can't get my link to work

*d2_electricalcircuitdiagrams_2000.pdf

Andy Warren · Nov 4, 2021

discool said:
If you don't have the disco 2 fuse box details, then here it is.

So looking at them diagrams you kindly sent, the relay is for the electric rear windows. I was hoping it would be for the HRW as the fault would probably be before the FB with the relay removed. On my pdf version of the D2 wiring diagram it shows a relay for the HRW on the internal FB but it must be soldered to the board so it looks like I'll just have to work through with the MM starting at the places suggested.

PopPops · Nov 4, 2021

Andy Warren said:
As mine blows F8 without the relay in am I right in thinking it would likely be between C0578-5 & C0584-5 ? HRW relay circled in blue & wiring to check *d2_electricalcircuitdiagrams_2000.pdf circled in red,hopefully.

No, to blow F8, the problem has to be after F8, either relay R138 in the IDM (unlikely but something in the IDM) or somewhere after CO582-4 which is the wiring to the HRW and mirrors. I have the electrical diagrams 03MY but I'm sure there would be no difference in this area. A problem between C0578-5 and CO584-5 would blow the 50A link in the engine fuse box rather than the 30A F8.

Andy Warren · Nov 4, 2021

PopPops said:
No, to blow F8, the problem has to be after F8, either relay R138 in the IDM (unlikely but something in the IDM) or somewhere after CO582-4 which is the wiring to the HRW and mirrors. I have the electrical diagrams 03MY but I'm sure there would be no difference in this area. A problem between C0578-5 and CO584-5 would blow the 50A link in the engine fuse box rather than the 30A F8.

Yeah now I know that is a window lift relay it has to be a short elsewhere. I wish I could get my rave CD to work on W10 as it's got the D2 electrical library on it (but I just 'aint clever enough with this stuff I've even tried the download with a virtual drive thing

but can't get that to work either

) as it would be handy just to know where the various connectors are located & what colour(s) they are, thanks again I'll let you know if/when I find the problem.

PopPops · Nov 4, 2021

Andy Warren said:
Yeah now I know that is a window lift relay it has to be a short elsewhere. I wish I could get my rave CD to work on W10 as it's got the D2 electrical library on it (but I just 'aint clever enough with this stuff I've even tried the download with a virtual drive thing but can't get that to work either) as it would be handy just to know where the various connectors are located & what colour(s) they are, thanks again I'll let you know if/when I find the problem.

Sierrafery posted a link in this thread, https://www.landyzone.co.uk/land-rover/interior-light-fault.371676/#post-5173594 to the electrical libraries etc which didn't need RAVE, they are just pdfs, https://www.dropbox.com/sh/47hbz40an5he5j2/AACH509eV_o7QhM5PoX6eFVLa

Could get round needing RAVE.

Stanleysteamer · Nov 4, 2021

Andy Warren said:
What a plank I am of course they're the radio aerials . Well that's one less thing to check. Like you not the best with electrickery but I'll start unplugging the door looms & checking the live supplies for shorts. I find it strange that even with the relay out it still blows so maybe it's between the 'battery' & the fuse box (where the HRW relay is). Thanks Stan.

No probs! hope you get to it!

sierrafery · Nov 5, 2021

The straight way to rule out the fusebox would be to unpin the wire from C0582 pin 4 and if the fuse blows that way too replace the fusebox

Andy Warren · Nov 5, 2021

sierrafery said:
The straight way to rule out the fusebox would be to unpin the wire from C0582 pin 4 and if the fuse blows that way too replace the fusebox

You are such a wealth of knowledge I don't know what we'd do without you, on that note could you tell me where to locate C0582 please

& I'll remove pin 4 & try it, many thanks.

Disco 2 TD5 HRW blowing fuses

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