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Installing relays in a 5a

Posted: Tue Mar 19, 2019 11:47 pm
by Timharwood69
Evening all
I want to install a new fuse box in my recently purchased 5a as the original has some burn damage but also want to install relays for the lights and fan. Does any have any wiring diagrams to show how to fit the relays.
Many thanks
Tim

Installing relays in a 5a

Posted: Wed Mar 20, 2019 12:07 am
by Dennis Nicholas
I believe that there are some circuit diagrams on this website somewhere but can't see where they have been put.....probably Peter Freeman's excellent coloured ones.

Dennis

Installing relays in a 5a

Posted: Wed Mar 20, 2019 12:13 am
by Timharwood69
Thanks for that Dennis will try and find them

Installing relays in a 5a

Posted: Wed Mar 20, 2019 6:00 am
by scimjim
Peters excellent wiring diagrams are here.

To install a relay, the cable that takes power from the switch is used to energise the relay (pin 86) via earth (pin 85) - this is the low current circuit. A fused supply from the battery is taken (pin 30) and fed to the component when the relay is energised (pin 87) - this is the high current circuit that would originally have gone through the switch.
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Installing relays in a 5a

Posted: Wed Mar 20, 2019 8:22 am
by philhoward
If you fancy something more "plug and play", loom and relay kits are available on eBay which plug straight into the original plug, such as https://www.ebay.co.uk/itm/Ceramic-H4-H ... SwnbZYEEVW

I've seen individual relays with labelled wires and a fuse in The Range of all places, but in searching found another wiring diagram which might give a fuller explanation:
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As we don't have negative switched headlamps on our cars, the grey wires shown off the pin 85 on the relays can just go to earth, and no need to pick it up from the headlamp connector either.

Installing relays in a 5a

Posted: Wed Mar 20, 2019 9:06 am
by Dennis Nicholas
scimjim wrote:
Wed Mar 20, 2019 6:00 am
Peters excellent wiring diagrams are here.

To install a relay, the cable .
Great Jim. Maybe even add the icing by putting the corresponding terminal numbers on the bottom two drawings.

I have another circuit drawing of a comprehensively relayed Scimitar that I was thinking about (one of our other members efforts) but that one is not among the "Peter" ones.

The Peter Freeman circuits are in the "How to" section.

I still find it very difficult to find anything on the "discussions" using the search facility.....it usually ends up showing endless forum pages that happen to have at least one of the search words......often literally hours of reading through to find something meaningful. Perhaps My IT skills are falling short and there is a more cleaver way to limit the search.?

Dennis

Installing relays in a 5a

Posted: Wed Mar 20, 2019 9:28 am
by scimjim
The images above are just from a google search - the first one has terminal numbers, the second one is to show high/low current and the explanation is in the text (85/86 are low, 30/87 are high).

You have to use very specific search words to restrict the number of hits.

For example, if I search for wiring diagram, I’ll get 81 pages back. If I search for noggin wiring (because I know they’re on the North East noggin page), I’ll get 4 pages and the third post down is a direct link. If I search for Freeman wiring (because I’m looking specifically for Peter’s wiring diagrams), I’ll get 7 pages - but again, there’s a direct link on the third post down.

Or I could just go to the FAQ/how to section :D

Installing relays in a 5a

Posted: Wed Mar 20, 2019 11:20 pm
by Timharwood69
Thanks for all the info it will be a great help, will crack on with that after I've overhauled the carb. The car has a rssoc sticker on the back so someone on here may have owned it. Its cream 1974 reg KTU886N.

Installing relays in a 5a

Posted: Wed Mar 20, 2019 11:25 pm
by Timharwood69
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Installing relays in a 5a

Posted: Tue Mar 26, 2019 1:58 am
by Roger Pennington
Timharwood69 wrote:
Wed Mar 20, 2019 11:20 pm
The car has a rssoc sticker on the back so someone on here may have owned it. Its cream 1974 reg KTU886N.
Ah! KTU886N back again! :D

That's the car that came from the Stondon museum when they sold some of their stock. A previous owner (perhaps the one you bought from?) introduced himself in Nov. 2014 in this thread here, and a few posts down on that page there's a post with a link to an earlier owner's project thread here dating from Jan 2013. So there's lots of reading on the forum, and lots of history behind your car.

Installing relays in a 5a

Posted: Tue Mar 26, 2019 11:51 pm
by Timharwood69
Thanks for that Roger have just read the thread, very interesting. Having gone through the car I realized that someone had spent time and money on it at some stage and was glad to find the timing gear had already been done! Rebuilt the carb over the weekend as it is not running properly but think that is down to the timing as it was popping and back firing, so the next job is to redo the valve/tappet gaps and static timing to get it running then get the strobe light out the back of the shed. Once that's done oil and coolant will be changed along with the hoses and hopefully back on the road.