I've got a S2A I'm fitting new front lights and light harness to.

When I got the vehicle the wiring was bodged about a bit so all the front light wiring got removed at the same time as several spot lights.. wire wrapped around chassis and hanging from under steering wheel and so on. Trust me it wasn't worth trying to keep.

I've got a front lamps harness from autosparks and am ready to fit it. My foot switch is live on the input pin when the headlights are switched on, and the output pins for dip (UR) and main (UW) are each made live in turn as I toggle the foot switch. So far so good.

Now I think I just run wires from those pins out the footwell to join the loom in the engine bay and connect straight to my new lamps harness, right? They don't need to go anywhere else first?

At some point the feed to the main beam warning light has got lost. I've checked the bulb, it's fine and earthed. For this I was thinking about running a wire back from the new main beam (UW) wire in the engine bay once it's there, and in behind the dash to power it like that. Thought was to splice it into the wire that's on the bulb now as I'm not sure how to disconnect it from the bulb holder.. it seems like it might be soldered, which I could do with the new one I suppose..

I'm not fitting halogen lights so I don't think I need any relays.

Thoughts?

From what I recall 2a only has two fuse's, still it sounds like you have a plan, but just fit a cut off switch in case of problems.

Unless its a resto I'd run the main and dip wires to the front then fit a pair of fused relays with short power supplies from the battery. gives much better lights that are fused and drops the current throught the dip switch and ign. Put the relays near the rad panel. Costs about £5 and solves a lot of issues.
https://www.ebay.co.uk/itm/2-X-30A-...424253?hash=item3daa6003fd:g:mxEAAOSwEzlfT2Qs

Ok. I've not done much electrics before. Having read up a bit I agree relays sound like a good idea.

I could mount a pair on the rad panel on the O/S near my battery. I've read supplying them from the starter solenoid is a good idea, but I don't know why that would be better than the battery? Other than I'm not sure I like the idea of cluttering up the +ve battery post if I'm honest. What do you think?

The relays you linked are 30A, which I take to mean the relay itself as well as the fuse? I expect about 10A going through my two headlights (at about 55W each). If so I should put a 10A fuse in those relays, but could then put a higher one in later (up to 30A) if I wanted to run some spots off the main beam too at some point - just an example to see if I understand how they're rated..?

scottonthefen said:

just an example to see if I understand how they're rated..?

Click to expand...

Yes, the relays appear to be 30A rated at 12v dc and fused accordingly. The often overlooked electrical requirement is that the cable should always be capable of blowing the fuse under a fault or short circuit condition. So wire capable of carrying 30A will be needed if you leave them fused as supplied. I would downrate the fuse and cable to suit your load requirement.

15A fuse should be enough, that 12x15 = 180W which gives you a margin over 2 x 60W heads. Runing supply from solenoid is simple becuse its east to put a connection on. If you use battery terminal then take one decent wire to an insulated termail block as there are sure to be other thing you will want. The way you power the headlamps switch will determine whether the headlamps will come on with or without ign on, not the supply from the battery.

Thanks. I've ordered the bits I'll need, and I'll use 15A fuses. I take it I only need the thicker wire on the hot/positive side of the fuse? Not the lamp side aswell?

Wire should be able to blow a 15A fuse without melting. This applies all the way to the lamps. Easy way to think about it is to imagine a short circuit applied anywhere on your circuit. Will the fuse blow in every case?? Fuses protect cables from melting primarily.

ok. I've been wondering what the headlamp wiring on the autosparks front light harnesses I have here is rated for. Seems there's no point using a fuse in the relay any higher than what that wiring would take.. regardless of what I run from the solenoid to the relays as a feed.