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I'm looking at a 3 contact electrical box with connections - c1,c2 and w1. It's parked close to the o/s horn (both horns not working - although they do if I wire straight to the battery). Could this be a horn relay?. can I bridge the wires to use the horns directly? If I need to get a modern replacement will it have the same 3 connections? Any help gratefully received, thanks.

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Hi Roger (Owen). The Lucas relays uses the following terminology: C means contact so C1 and C2 are each a contact that are connected when the relay is powered. W means winding so W1 and

If you use that new relay the pin connections are numbered rather than lettered.  The equivalents are 85 =W1, 86=W2 (the earthed body of your Lucas relay) , 30=C1, 87=C2

Common fault is earthing the casing.  Double check that. Beyond that you can open it up and clean the mechanism of contacts and solenoid arm.   They look so much more Cpt Nemo than a modern plast

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Hi Roger,

you actually have four connections as the body is earth. 

You must use a relay as the horn current may well burn out the plunger in the horn push.

Any modern relay will work.

I would suggest getting one where you need a separate earth wire as this ensures a good return.

These are good ones http://www.vehicle-wiring-products.eu/product.php/642/12v-4-blade-type-b

You can get a bracket that the relay plugs into and helps attach to the car body.

These relays are also very good if you want to power the headlights via relays.

 

Roger

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43 minutes ago, RogerH said:

Hi Roger,

you actually have four connections as the body is earth. 

You must use a relay as the horn current may well burn out the plunger in the horn push.

Any modern relay will work.

I would suggest getting one where you need a separate earth wire as this ensures a good return.

These are good ones http://www.vehicle-wiring-products.eu/product.php/642/12v-4-blade-type-b

You can get a bracket that the relay plugs into and helps attach to the car body.

These relays are also very good if you want to power the headlights via relays.

 

Roger

Thanks Roger - those seem great, and not expensive. I'll just need to be careful with the wiring.

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Hi Roger (Owen).

The Lucas relays uses the following terminology:

C means contact so C1 and C2 are each a contact that are connected when the relay is powered.

W means winding so W1 and W2 are the ends of the winding.

The three connection horn relay joins W2 to one of the contacts internally (I don't remember if it connects to C1 or C2), so only shows terminals labelled W1, C1 and C2. This normally means you have a single supply to the relay at whichever of the Contacts is internally connected to the Winding. Then W1 connects to the horn push and the remaining Contact terminal connects to the horn.

It is relatively simple to determine which Contact is internally connected to the winding:

1.  Connect W1 to the -ve of  a 12 volt battery,

2.  Connect the +ve battery terminal to C1. If the relay clicks, C1 is directly connected to the winding,

3.   If it doesn't click, then connect +ve to C2 and the relay should click showing that C2 is connected to the winding.

I hope that helps

Kind regards

Tony

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If you use that new relay the pin connections are numbered rather than lettered. 

The equivalents are 85 =W1, 86=W2 (the earthed body of your Lucas relay) , 30=C1, 87=C2

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Common fault is earthing the casing.  Double check that.

Beyond that you can open it up and clean the mechanism of contacts and solenoid arm.   They look so much more Cpt Nemo than a modern plastic relay.

Peter W

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Ah the Lucas 6RA relays. I have spent a lot of time collecting a few of these relays to put on my TR. The horn relay is no longer available from the Triumph suppliers. Mine is an R246 made in Bedworth England. As Tony says above the horn push connects to W1. Power connects to C2. When the horn push is pressed then C1 connects to C2 (power). C1 connects to the horns.

So in the absence of a direct replacement you can use another type of Lucas 6RA relay. Beware however because just because it says 6RA doesn't mean it is the right one. 6RA refers to a generic group of relays. The one to find is one with the numbers 33213, 33293 or 33302 followed by a letter. After the numbers it say 12v and then the next 3 or 4 numbers tell you the week and year of manufacture. For example 33213J 12v 4571 or 33293A 12v 568. The mounting bracket should be on the side of the casing what Lucas call H1 type housing. H2 have the bracket on the top and H3 don't have a bracket at all. I believe these relays are also fitted to Triumph Stags. These relays are 'normally open' types which means there is no connection between C1 and C2 until you power up the winding. Note some relays have a double Lucar connector for C1 and some have single but doesn't affect how you wire it up. I think this relay is also the same as part number 142169A or type SRB101 or SRB111.

So fit the 6RA relay to the car. Connect horn push to W2 and connect W1 to power. Connect main power supply to C2 (this has an in line fuse) and C1 to horns.

If you prefer one with the bracket on the end opposite the terminals then the number on the relay will be 33311 (also called SRB112) with maybe a letter D after the number. Wiring will be the same.

Looks better (more period) than the modern plastic types I think.  

Although many early Triumphs didn't have a horn relay I would recommend you use one to protect the horn push circuit that has thinner wires. Try to get the one you have working. They are pretty simple devices.

Beware also that also included under the 6RA 'umbrella' are 24v as well as 12v types and others are normally closed and there are also 'change-over' circuit types.

Keith

Edited by keith1948
part number should be 142169A not 142196A
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Thanks Rob I have the table of relays you provided the link to. It is very useful but you still need to know exactly what you are looking for at an auto jumble. Easy to buy a 24v one by mistake!

Anyway I think I have identified the relay in Roger Owens original post. It looks like a Lucas type 33135/SB40 relay. It is 12v normally open type with mounting bracket at the end (H2) and ok up to 20A. In the Holden catalogue (see link) it was used on early XK Jaguars and early DB Aston Martins.

However the connection W2 seems to be missing which may explain why it won't work. My guess is that if you put power across W1 and the rivet where W2 should be then you will get a switched circuit across C1 and C3 (which you have as C2). It may also be that your particular relay might be wired internally so W2 is the casing so check that out first.

Make sure that none of the C contacts or W1 touch the case or you will short it to earth. Don't like the design of this relay because the thickness of the insulation is all that separates these contacts from shorting out on the case. It will do the job though.

https://www.holden.co.uk/p/lucas_type_33135_sb40_relay

Holden do the SRB111 6RA type of relay that is the one you need.

Keith

 

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Hello Jim

12 hours ago, Tr4aJim said:

Keith,

Is this the correct relay?

https://www.s-v-c.co.uk/product/6ra-relay/

Jim

 

The link you gave to SVC shows a picture with different bracket positions and pin outs for the SRB111 relays in the photo so not sure what they are selling. See if they can send you more information. SRB111 should have the bracket on the side and only 4 contacts (W1 W2 C1 C2). The problem with some (many) aftermarket 6RA relays is that they don't have the 33... numbers or dates on so you have to rely on the other description such as SRB111 or part number 142169.

There are parts suppliers in USA e.g.

https://www.bpnorthwest.com/catalogsearch/result/?q=relay

This supplier has Lucas type SRB111at $37  and TR6 part number 142169 at $17. They are basically the same relay.

Why there seems to be so many different numbers for what is basically the same relay is confusing. For example SRB111 (33302) and SRB112 (33311) only differ in that the first has the bracket on the side and the second has it on the top. If you look at the link RobH posted above you will see that you can use several different 6RA relays to do essentially the same job. The only ones to avoid are the double contact and changeover types and those that are 24v and the normally closed types. (Although in saying that I came across someone who had used several normally closed relays to power his headlights. I have no idea how he would have wired them up.)

Try a supplier in the USA although we might be nearer to you than Oregon.
Keith

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Hi Jim,

For clarification the period Lucas catalogues show that two types of 6RA relays were fitted to the TR4A.

A horn relay "only" used on the TR4A - Lucas 6RA 33188

73816247_Lucas6RA33188HornRelay.thumb.jpg.3b81e2cb6b674dd666ef5fc027e3d364.jpg

 

Plus the overdrive relay ( used on the T4 to TR6 ) - Lucas 6RA 33213

713103423_Lucas6RA33213O.D.Relay.thumb.jpg.9f51d979f50406a1ed4c40e0c8845538.jpg

Regards, Richard

 

 

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Richard, Keith, thanks!

I did notice that BPNW has a Tr6 Lucas horn relay for $39, and a “no-name” relay for $17. Past experience has taught me to avoid the cheap ones.

FYI - With shipping, the $39 BPNW relay listed for the Tr4a is just a dollar cheaper than getting it from SVC. 

I looked up the Stanpart number on the TRF site, and they list two parts, one of which is NLS (see attached). Were different relays used based on which horns were installed? 

Moss US, does not have a horn relay listed.

Jim

C5D6985C-8A3A-4B4D-8258-5112F133C933.thumb.jpeg.a8ca3657ec3cb12273771cac6edf64ee.jpeg

Edited by Tr4aJim
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On 8/2/2019 at 11:10 PM, RobH said:

If you use that new relay the pin connections are numbered rather than lettered. 

The equivalents are 85 =W1, 86=W2 (the earthed body of your Lucas relay) , 30=C1, 87=C2

That's great, thank you!

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3 hours ago, Tr4aJim said:

Richard, Keith, thanks!

I did notice that BPNW has a Tr6 Lucas horn relay for $39, and a “no-name” relay for $17. Past experience has taught me to avoid the cheap ones.

FYI - With shipping, the $39 BPNW relay listed for the Tr4a is just a dollar cheaper than getting it from SVC. 

I looked up the Stanpart number on the TRF site, and they list two parts, one of which is NLS (see attached). Were different relays used based on which horns were installed? 

Moss US, does not have a horn relay listed.

 

I get confused about this stuff as I wrote the electrical sections of the Moss Europe Triumph catalogues - and the Moss USA end of the business quite rightly  rehash that work to match the way they sell.

Moss USA list this for TR4A horn relay - but do not list a TR4 ! Moss No 131-520  https://mossmotors.com/relay-brake-warning-light?assoc=71280   A plastic thing titled 'brake warning light' - What more do we expect from a MG specialist?

They do stock Triumph pt no 142169, which will do the job, as Moss pt no 542-170 https://mossmotors.com/relay-overdrive-push-on-terminal

 

 

Cheers

Peter W

 

3 hours ago, Tr4aJim said:

Jim

C5D6985C-8A3A-4B4D-8258-5112F133C933.thumb.jpeg.a8ca3657ec3cb12273771cac6edf64ee.jpeg

 

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I've opened up the relay, points look worn and there's a bit of corrosion. After a clean up I connected the coil to a bench power supply and the relay seemed to work, but on reconnecting..... still no horns. Can't see how the case acts as an earth though as all the contacts are insulated by the bakelite.   

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IMG_2138.JPG

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SB40.jpg.9a55a32689ca38b92a760118225b8e6f.jpg

Aah - that is an SB40 relay not a 6RA. The case certainly should be the earth connection.  Unfortunately your photo of the internals doesn't show that side so we can't see how the case connection should be made.

SB40.jpg.c86e3559ebb992df957a5305f992518c.jpg

 

 

Edited by RobH
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4 hours ago, RobH said:

SB40.jpg.9a55a32689ca38b92a760118225b8e6f.jpg

Aah - that is an SB40 relay not a 6RA. The case certainly should be the earth connection.  Unfortunately your photo of the internals doesn't show that side so we can't see how the case connection should be made.

SB40.jpg.c86e3559ebb992df957a5305f992518c.jpg

 

 

Thanks - that is interesting. Maybe 'from switch' is the earth (open circuit). when closed - continuity maintained and carried to the horns by their grounding???

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 Those labels are just a general generic  indication  - not specific to your application, it's just a drawing I found of the SB40 relay so ignore the words. As for other Lucas relays it comes in different styles.

 According to the wiring diagram for the '4A,  W1 goes to earth via the horn button.  Power comes from the battery via a fuse to C2 and there must be an internal connection in the relay between C2 and what would be W2 so that the volts go both to the contact and one end of the relay coil. Apparently with your version of the relay there is no earth connection so apologies for any confusion. 

It also means my earlier post re connections for a modern relay needs amendment.  86=W2 should be linked to 87=C2  and there is no earth connection. 

 

Edited by RobH
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