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Rodney Peach
Experienced User
Username: rodney

Post Number: 89
Registered: 12-2003
Posted on Saturday, 03 August, 2019 - 00:46:   Edit PostDelete PostView Post/Check IP

Hi All ,
Horns stopped working , I have looked into some threads , but I am confused my shadow has 1 horn under each front wing , not on left only ? I checked fuse Ok ! checked the part on steering wheel not worn OK ! in some threads there are mentions on a relay but I have relays on both sides of engine compartment but don't know which one ? took a wire to sump and with help bushing horn the right hand side one sounded ?? I am a fillet lost can anybody help as have to go to MOT , I see some in threads are different under hood being Australian models or USA , mine is uk RHD

Regards
To All
Rodney
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Robert J. Sprauer
Frequent User
Username: wraithman

Post Number: 484
Registered: 11-2017
Posted on Saturday, 03 August, 2019 - 01:07:   Edit PostDelete PostView Post/Check IP

There is a horn relay mounted next to the hi-beam relay on the radiator support. On USA cars it is on the left. It would be informative to look up component location (electrical) within the TSD manuals. Make sure you look at RHD versions.
heritage.bentleymotors.com/en/technical-library
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2899
Registered: 06-2009
Posted on Saturday, 03 August, 2019 - 01:25:   Edit PostDelete PostView Post/Check IP

The component location diagram is right at the start of Chapter M, and is shown as being almost directly behind the left hand side headlights on said diagram (and that's regardless of LHD or RHD for the horn relay).
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Mike Thompson
Frequent User
Username: vroomrr

Post Number: 819
Registered: 04-2019
Posted on Saturday, 03 August, 2019 - 02:45:   Edit PostDelete PostView Post/Check IP

Hola como estas,

On my car because the wires are so old and brittle I had wiring problems. I had to do some rewiring. The right hand side supplies the left hand side electricity and when I hook up the left hand side there is not enough electricity to sound both horns. For now I only need one horn. It only needs to beep to pass inspection.
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Robert J. Sprauer
Frequent User
Username: wraithman

Post Number: 485
Registered: 11-2017
Posted on Saturday, 03 August, 2019 - 03:18:   Edit PostDelete PostView Post/Check IP

The horn relay is the top one.
Note: One thing that is overlooked are the ground points. The manual shows where they are and they should be disassembled, cleaned and coated to prevent corrosion. Your electrical terminals may be clean at the relays but if it can't see ground nothings happens.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2900
Registered: 06-2009
Posted on Saturday, 03 August, 2019 - 03:53:   Edit PostDelete PostView Post/Check IP

A big, honkin' second of Mr. Sprauer's observation!!

It seems to be a big problem on many British (and other, but my experience is mostly with British) cars of a certain age that the ground connections go wonky.

I make a point when taking apart anything electrical, including ground connections, to mechanically clean them when I can, chemically clean them when I can't, and to apply electrically conductive grease when putting it all back together.

I have not yet ever needed to revisit any connection where I did this.

Brian
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Mike Thompson
Frequent User
Username: vroomrr

Post Number: 820
Registered: 04-2019
Posted on Saturday, 03 August, 2019 - 05:08:   Edit PostDelete PostView Post/Check IP

Brian, I'm thinking you are talking about this one in red? (Not sure what the one in blue is.)

horn

Not sure if that is the location of a Shadow I or Shadow II my car is both.
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Robert J. Sprauer
Frequent User
Username: wraithman

Post Number: 486
Registered: 11-2017
Posted on Saturday, 03 August, 2019 - 05:55:   Edit PostDelete PostView Post/Check IP

The red arrow is the relay.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2901
Registered: 06-2009
Posted on Saturday, 03 August, 2019 - 06:14:   Edit PostDelete PostView Post/Check IP

If the relays are the original Lucas relays, all of them will have the basic rectangular shape and metal cover, regardless of the tab style used for mounting. (Or even the number of terminals, as the starter relay is the same size and shape as far as the case goes, but the terminal arrangement is quite different than the typical relay used for other purposes).

If a car was produced before 1977 it is an SY "one series" car and 1977-80 is an SY2 series.

Brian
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Robert J. Sprauer
Frequent User
Username: wraithman

Post Number: 487
Registered: 11-2017
Posted on Saturday, 03 August, 2019 - 06:23:   Edit PostDelete PostView Post/Check IP

Location on my 1980 SWII

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Rodney Peach
Experienced User
Username: rodney

Post Number: 90
Registered: 12-2003
Posted on Saturday, 03 August, 2019 - 07:10:   Edit PostDelete PostView Post/Check IP

Hi All
Thanks for help I have 3 there see photos if you can see ? if I put a new earth will it solve both horns then? Electrics is to my good point, and here near me to leave it somewhere where they less than me frightens me
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Robert J. Sprauer
Frequent User
Username: wraithman

Post Number: 488
Registered: 11-2017
Posted on Saturday, 03 August, 2019 - 07:34:   Edit PostDelete PostView Post/Check IP

The contacts within the relay can can be corroded. No harm in gently prying off the cover and cleaning things up.....But first...make sure you write down what wire goes to what terminal. There is only one horn relay. Lucas 6RA
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2902
Registered: 06-2009
Posted on Saturday, 03 August, 2019 - 09:31:   Edit PostDelete PostView Post/Check IP

And for those doing relay replacement the Lucas 6RA can be easily replaced by any "Bosch type" relay, and these are dirt common and far less expensive.

I've also done the "pop the case off" and check what's going on inside method of cleaning up the contacts inside a Lucas relay.

Yes, you lose the original look, and if that's important to you then stick with the Lucas. But if cost, availability, and functionality are as important or more important to you than originality there are more readily available options.

Lucas to Bosch Terminal Diagram

Brian
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Mike Thompson
Frequent User
Username: vroomrr

Post Number: 823
Registered: 04-2019
Posted on Saturday, 03 August, 2019 - 09:48:   Edit PostDelete PostView Post/Check IP

Rodney, ¿Entiende inglés lo suficiente como para entender lo que estamos diciendo? Dijo que puedes desmontar el relé y limpiarlo un poco, pero asegúrate de volver a colocar los cables como los quitaste. También dijeron que limpiar los cables de tierra y aplicar grasa conductora de electricidad al volver a armar todo. Esto debería ayudar. Si nada de esto ayuda a tratar de reemplazar el relé, si eso no ayuda, revise todos los cables.

Moderator Translation:

Do you understand English enough to understand what we are saying? He said you can disassemble the relay and clean it a bit, but be sure to replace the wires as you removed them. They also said to clean the ground wires and apply electrically conductive grease when reassembling everything. This should help. If none of this helps to try to replace the relay, if that doesn't help, check all the wires.
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Rodney Peach
Experienced User
Username: rodney

Post Number: 91
Registered: 12-2003
Posted on Saturday, 03 August, 2019 - 20:10:   Edit PostDelete PostView Post/Check IP

THANKS ! to you all will look into that ! but no clicking either from any relay when I push horn but will see and clean it if its the one I think its in a right place behind air con condenser !! and Thanks Mike I do understand I am English been out in Spain for years but speak both .
Just where I am situated in the north in Galicia not any good mechanics here

Will let you know how I get on !
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Robert J. Sprauer
Frequent User
Username: wraithman

Post Number: 489
Registered: 11-2017
Posted on Saturday, 03 August, 2019 - 21:18:   Edit PostDelete PostView Post/Check IP

The round canister is the A/C drier.
The condenser is between the front grill and radiator.
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ross kowalski
Prolific User
Username: cdfpw

Post Number: 1192
Registered: 11-2015
Posted on Saturday, 03 August, 2019 - 23:25:   Edit PostDelete PostView Post/Check IP

Robert,

I know you get this a lot but it still is worth noting. Wow that's one clean car.

The only time I have had cars that sorted were the first two days when brand new.
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Robert J. Sprauer
Frequent User
Username: wraithman

Post Number: 490
Registered: 11-2017
Posted on Sunday, 04 August, 2019 - 00:14:   Edit PostDelete PostView Post/Check IP

Thanks Ross. Actually due to another cut and polish of the paint there is residue that an be seen all over.
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Rodney Peach
Experienced User
Username: rodney

Post Number: 92
Registered: 12-2003
Posted on Sunday, 04 August, 2019 - 01:41:   Edit PostDelete PostView Post/Check IP

Hi

Yes sorry ! relay is behind the a/c drier , my mistake

Regards
Rodney
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Rodney Peach
Experienced User
Username: rodney

Post Number: 95
Registered: 12-2003
Posted on Monday, 05 August, 2019 - 02:25:   Edit PostDelete PostView Post/Check IP

Hi All finally dismantled relay Lucas 6RA WHAT A PLACE TO PUT IT ! HAVE 4 WIRES GOING TO ALL CONNECTIONS APART FROM W2 ? OPENED IT ITS LIKE NEW ! SO PUT A EARTH TO ENGINE SOMEBODY PUSHING HORN AND NOTHING LIGHTS UP WITH MY BULB TESTER SHOULD I NOT HAVE POWER TO ONE OF THESE WIRES WHEN HORN IS PUSHED ? LIKE I SAID FUSE OK STEERING WHEEL OFF AND ONE ONE WIRE TO HORN MUST BE LIKE THAT NO?

REGARDS RODNEY
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Robert J. Sprauer
Frequent User
Username: wraithman

Post Number: 491
Registered: 11-2017
Posted on Monday, 05 August, 2019 - 02:51:   Edit PostDelete PostView Post/Check IP

http://rrtechnical.info/SY/TSD4200/m/m4.pdf
Horn schematic and trouble shooting guide. Learn how to access the service manuals. They will provide repair and diagnostics to everything on the car.
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Robert J. Sprauer
Frequent User
Username: wraithman

Post Number: 492
Registered: 11-2017
Posted on Monday, 05 August, 2019 - 02:55:   Edit PostDelete PostView Post/Check IP

the horn button merely provides the ground for the relay coil enabling it to pull the contacts that make the voltage flow to the horns. There are 2 fuses involved...see the diagram
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2906
Registered: 06-2009
Posted on Monday, 05 August, 2019 - 04:03:   Edit PostDelete PostView Post/Check IP

By the way, if anyone wants the full Workshop Manual for either the SY1 or SY2 series, OCR processed so that all the documents are searchable via Windows Search (provided you index PDFs), then feel free to download:

TSD2476 Silver Shadow and Bentley T "One Series" Workshop Manual - OCR Processed

TSD4200 Silver Shadow II and Bentley T2 Workshop Manual - OCR Processed

Credit still goes to the folks at the RROC-A who scanned these back in the day when OCR as part of scanning was not the default (and wasn't nearly as good as it is now for "fuzzy" originals). All I did was download every bit of the material and post-process it with a newer OCR engine. That's all I take any credit for, along with creating a "download the whole thing in one fell swoop" repository.

Brian
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2907
Registered: 06-2009
Posted on Monday, 05 August, 2019 - 04:16:   Edit PostDelete PostView Post/Check IP


quote:

the horn button merely provides the ground




Which brings us back to your very wise advice much earlier in the topic.

If one tests for continuity when the horn button is depressed, and finds it present, then start searching for the end point where the ground wire for the horn is located after passing through the horn switch, first. It would not shock me to find that corroded, loose, or possibly both.

A great many of the dash lights on SRH33576 came back to life after I cleaned up all of the grounds for them. There have been other bits where bad ground was the culprit, too.

All of the above presumes, of course, that the relay itself has been tested to ensure that the normally open (C1) terminal does actually get closed when you pass 12 volts between W1 and W2. I long ago created a testing line out of a very long extension cord (standard lamp type) on which I put clamps to attach to the battery terminals, alligator clips for the opposing end [relay in this case] and a thumb wheel switch to turn the juice off and on. In a relay you should hear, possibly even feel, the click of the switch closing. If you're working with a solenoid rather than a relay, you can definitely feel and hear it open close and see same if you're looking through it (as it might not open/close completely).

The horns are covered in Chapter M14 and after looking at the wiring diagram I found exactly what I expected: that terminal C3 (normally closed) will have nothing attached to it and possibly have a rubber boot over it.

Brian
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2909
Registered: 06-2009
Posted on Monday, 05 August, 2019 - 05:38:   Edit PostDelete PostView Post/Check IP

By the way, and why I failed to mention this earlier I do not know, if you use the test line to activate the relay, and the horn blows, you have isolated the issue to the wiring between the horn relay and ground.

If you know the horn switch is working, then it's either the wiring running between terminal W2 and the switch or the wiring from the switch itself to ground. I'd suspect the latter before the former, but check both.

Brian
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Rodney Peach
Experienced User
Username: rodney

Post Number: 96
Registered: 12-2003
Posted on Monday, 05 August, 2019 - 09:08:   Edit PostDelete PostView Post/Check IP

Good evening all ,
2 fuses for horns ? Thought only one?

Good night
Rodney
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Larry Kavanagh
Frequent User
Username: shadow_11

Post Number: 479
Registered: 05-2016
Posted on Monday, 05 August, 2019 - 10:30:   Edit PostDelete PostView Post/Check IP

Two fuses on the fuseboard supply the horns i.e., fuses 7 & 14. Fuse 7 also supplies the headlight flash. If the headlight flash is working then fuse 7 is OK, if not then fuse 7 is probably blown. If fuse 7 is OK check fuse 14. See the workshop manual TSD4200, Electrical Section Part 4, Para. M14 Horns.
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ross kowalski
Prolific User
Username: cdfpw

Post Number: 1193
Registered: 11-2015
Posted on Monday, 05 August, 2019 - 12:04:   Edit PostDelete PostView Post/Check IP

Rodney,

A real handy tool that I love for relay work is a powered test probe. It will tell if what you are probing is 12v+ , earth, or floating and with a press of a button it will send 12v+ or earth to the probe.

I bought one from Amazon called the ALLOSUN EM285 Electric Circuit Tester for $24 USD and use it all the time. I haven't touched my test light since I got the probe and I love test lights.

Ockham's Razor being what it is checking 7 and 14 is a good start. I would make sure that thoses fuses are good before any further testing.

Luck.
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Geoff Wootton
Grand Master
Username: dounraey

Post Number: 2132
Registered: 05-2012
Posted on Tuesday, 06 August, 2019 - 01:30:   Edit PostDelete PostView Post/Check IP

Hi Ross

Having yesterday turned the two long wires I use for testing parts into a mini arc welder, I think it's time I invested in this tool.

Is the cable long enough to reach all parts of the engine bay, front lights etc, given the Silver Shadow's battery is in the trunk?

I normally use a separate free standing battery and I see the Allosun has a separate earth clip which will unify the earths. I know the standalone battery would be fine for delivering 12v, but what about continuity testing where the Allosun will need to be connected to the car's battery.
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ross kowalski
Prolific User
Username: cdfpw

Post Number: 1194
Registered: 11-2015
Posted on Tuesday, 06 August, 2019 - 02:14:   Edit PostDelete PostView Post/Check IP

Geoff,

I think it would reach but I just clip onto something live and a ground in the engine bay.

On your test lead, add a circuitreaker. I have a 30 amp one on the 15' jumper wire I keep in the Shadow.

It's to power the coil in the event of an electrical FTP.
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Geoff Wootton
Grand Master
Username: dounraey

Post Number: 2133
Registered: 05-2012
Posted on Tuesday, 06 August, 2019 - 02:36:   Edit PostDelete PostView Post/Check IP

Thinking about it I may wire in a dedicated live terminal into the engine bay, suitably switched, covered and fused. I have the same problem with my timing light, so now would be a good time to do it.

I think the Allosun would fulfil all my requirements so I can ditch the test leads.

Thanks for your reply.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2910
Registered: 06-2009
Posted on Tuesday, 06 August, 2019 - 08:39:   Edit PostDelete PostView Post/Check IP

Geoff,

I failed to mention, and your post points out how important it is, that if you are creating a test line that connects directly to the battery that you must put a fuse in it on one of the two lines, preferably near to the battery end since it keeps it out of your way.

I've had one incident where I accidentally shorted my tester and having that fuse is what prevented "arc welder effect" from occurring.

I could swear I once posted a photo of my contraption when I was covering how to test the coolant level amplifier, and as it happens, I did, in the document UD19427 Rolls-Royce/Bentley Coolant Level Amplifier Repair

Brian
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Geoff Wootton
Grand Master
Username: dounraey

Post Number: 2135
Registered: 05-2012
Posted on Tuesday, 06 August, 2019 - 10:19:   Edit PostDelete PostView Post/Check IP

Hi Brian

I was being lazy. I'm currently reconditioning the heater servo motors on the workbench and needed a 12v supply, which I ran from a spare car battery. I, of course, forgot about the wires which were lying on the bench and the two ends touched. I pulled them apart within 2 seconds - enough time for them to get very hot, but not so hot I burned my fingers.

The Allosun is now ordered - should be here later in the week.
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ross kowalski
Prolific User
Username: cdfpw

Post Number: 1196
Registered: 11-2015
Posted on Tuesday, 06 August, 2019 - 12:53:   Edit PostDelete PostView Post/Check IP

Geoff,

Tip on the powered probe, if you press the button to send 12v to something and the resistance is such that there is more than a few amps it has an internal breaker that shuts the power off. If you do that, you just unhook the cables from power and hook them back up.

It probably said that in the instructions (not that I read them)
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Geoff Wootton
Grand Master
Username: dounraey

Post Number: 2136
Registered: 05-2012
Posted on Tuesday, 06 August, 2019 - 13:40:   Edit PostDelete PostView Post/Check IP

Thanks Ross - and for the original recommendation.
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Rodney Peach
Experienced User
Username: rodney

Post Number: 98
Registered: 12-2003
Posted on Tuesday, 06 August, 2019 - 16:42:   Edit PostDelete PostView Post/Check IP

Hi All,

Fuses are ok ! 7 and 14 , horn works connected directly to a battery ! so as I said electrics is my weak point will buy the tester you mention Ross ! and try if not have to find a good electrician cannot be much absolutely everything else works fine and always has electrics ! cannot understand the horn part 1 wire to steering wheel normally 2 on other classics but parts are like new too.

Regards

Rodney
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ross kowalski
Prolific User
Username: cdfpw

Post Number: 1197
Registered: 11-2015
Posted on Tuesday, 06 August, 2019 - 22:14:   Edit PostDelete PostView Post/Check IP

Rodney,

If you look at the post Brian did of that relay there are two "w" terminals.

If you attach one of those to earth and one to 12v the solenoid will activate and make a click sound.

So

If there is a 12v+ wire on one of those "w" terminals and the other "w" terminal wire goes to the horn, if the horn could go to earth when you press it ( which it should) the relay will activate with a click sound.

Luck.
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ross kowalski
Prolific User
Username: cdfpw

Post Number: 1198
Registered: 11-2015
Posted on Tuesday, 06 August, 2019 - 22:17:   Edit PostDelete PostView Post/Check IP

Rodney,

Also if you get that tester I can write up the tests one would need to do to fix this.

I can't film it for you because I'm on holiday.
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Rodney Peach
Experienced User
Username: rodney

Post Number: 99
Registered: 12-2003
Posted on Tuesday, 06 August, 2019 - 23:19:   Edit PostDelete PostView Post/Check IP

Hi Ross ,

Thanks just put here back in garage since I have been fumbling about speedo does not count miles or trip speed working that's all . don't know if it can be something to do with this ? I filled her up tripped to 0 and had 10 miles now been stood here no go ? these are electronic no? from what I see 1997 shadow 2



What a nightmare with a few things


thanks to you all Cheers Rodney
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 2912
Registered: 06-2009
Posted on Wednesday, 07 August, 2019 - 01:27:   Edit PostDelete PostView Post/Check IP

The speedometer/odometer on the two series cars is electromechanical and not driven by a speedometer cable.

The actual gears in these things have been known to disintegrate over time.

If it's just the trip odometer I'd try resetting it again to see what happens. If it's the main odometer it's probably far more likely to be an issue with the gears having broken than an issue with the electrical connection, but you should still definitely check that first.

I have a section dedicated to Clock & Dashboard Instrument Repairs in the RR & Bentley Parts, Repair, Restoration & Other Resources Compilation, but all of the companies are located either in the US or one in Canada.

Brian, who once had a brief "odometer pause" on SRH33576 (for about 2 or 3 miles, back in 2007, that has never recurred)
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Rodney Peach
Experienced User
Username: rodney

Post Number: 100
Registered: 12-2003
Posted on Wednesday, 07 August, 2019 - 04:28:   Edit PostDelete PostView Post/Check IP

Hi Brian,t

thanks will look into it too ! never had any problems and they come in threes don't they and hardly use them only now and again never in winter ..


Cheers Rodney
Rodney

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