Martin wrote:

Bosch will be great. Just make sure they are "Form B": terminals 30 and 87 should be opposite each other, terminals 85 and 86 should be opposite each other:


Click image to enlarge

sako243 wrote:

Just a word of warning about the Bison kit. It only takes the trigger feed from one headlight which means if there's an issue with the wiring to that light it takes out both. The factory LR wiring has four fuses with four feeds to the headlights which means if a wire breaks to a headlight then it only affects that headlight.

I had a rather disconcerting moment losing all headlights at 60mph alongside Loch Cluanie in the Highlands in a storm. Due to the alternator location I'd used the passenger side headlight on the 300Tdi which had chafed a wire in the loom as it went around the bulkhead corner.

Subsequently replaced with LED headlights and thus no need for the relays but it's gained the redundancy back of the original system.

Thats too bad. Red Bison has a great rep and I have not had issues before this relay issue. I do not prefer LED headlamps. I tested a number of manuafacturers and never found the light output of them to be what I was looking for. With this, I have been happy with uprated wiring and uprated bulbs in Hella housings. The redundancy is an interesting issue I will keep in mind but ultimatly happy to live with that risk. Bullbar and roof lamps for emergencies in my case

Martin wrote:

Automotive relays are highly standardised - what you have fitted and the ones you have found on Amazon are generic Chinese-made low cost 40A relays.

There are however, two terminal layouts - called "Form A" and "Form B". Factory relays on a Defender are "Form B", from what I can find out, those H4458 relays are also Form B.

So, any 4 pin 40A Form B relay will be a replacement.

I would personally not fit a cheap Chinese-made relay as a replacement - but don't think you are UK based so won't link to UK suppliers.