Wiring- Fuses/Relays etc

[skamanfrank]

Right, thinking of making up a new loom for the imp at some point over winter and adding fuses.

Question #1
Where abouts do the fuses go? In between output and switch, or before the switch?

Question #2
Do I need relays? I'm perfectly happy with accessories/lights etc coming on without the ignition on, so I'm not too fussed about using relays there. Only other thing is- I'll be going over to Halogen lamps, so will I need relays for these? Or is there some other reason I should be using them?

Also for my fuses, I'm not sure how many to use for headlights etc. Part of me is saying I should fuse each headlight seperately, so that if one goes I still have some lights. But then again, there's no reason why they should go really **tempting fate ** so I could just fuse each side?

At the moment I'm thinking:

Fuse #1- Right hand side headlights
Fuse #2- Left hand side headlights
Fuse #3- Indicators/hazards, interior light, cigarette lighter, horn, dashlights
Fuse #4- Wipers, washers, heater, fog + spot

How does that sound?
At the moment I'll only be doing the front end of the car. Plan is to just chop through the loom and stick a block connector in to connect back to front (new bit of loom). Easier that way, I don't understand everything that goes on at the back with regulators, control boxes and the like!


Cheers as always you clever folk you!

[mskinner]

Where abouts are you? I might be able to lend a hand with it if you are anywhere near croydon.

Fuses always go as close to the power source (i.e. battery) as possible. You want to minimise the unfused length as any short in an unfused wire will cause big problems

Relays arent necessary generaly as long as the switch is rated for the amperage. I always use them personally as it means you can keep the big fat high current wires out of the cabin, saving space and making routing easier. Also using a relay on the headlights etc usually results in a brighter light!

Number of fuses, ive only ever used 4 on a mini (similar wiring to an imp) but would prefer to have one per function really!

I usually wire the brakelights to a permanent live, along with the sides and hazards so that with ignition off they still work. Useful if being towed or you have to shut down the engine while moving for some reason.

Another trick I like to use is making the fusebox a bus bar. Single BIG cable soldered accross all the positive side terminals you want permanently live, and then I use a relay or 2 from this cable and triggered by the Ign switch for the Ign +, again a big cable soldered accross the + terminals on the fuses that you want to be an ign live.

Final tip for now: Use BIG wire for the headlights. I used decent speaker wire for my headlights, hugely over spec but now my lights rival HID in intensity!

[Mr K]

top advice, I'm going to be fitting a relay because the switch in the dash is poop and certainly cant handle a halogen bulb for long (although it has lasted a year now, pushing my luck going on what i have read on the reliant forum)

i have also heard its best to keep the relay as close to what its powering as possible; don't know how true it is, and mine will be behind the lights anyway.

quick question:
should i relay the lights together. i.e. one relay for dip, one for full, or should i do each light seperately ending up with 2 for full, 2 for dip.

lastly, is it neccessary to put a relay on the dipped side of the circuit? i had originally planned to use 1 relay on each light, only doing full beam.

[BiAS]

I'd personally go for 1 relay for dip and 1 for full beam, little bit higher rated than needs be, otherwise you may get a slight winking effect when you turn em on or off du to the relays reacting at different rates.

If you relay the dips you just take the load off the switch, which has got to be a good thing if the switch has a rep for being poop.

[Dorset_Clive]

Another top tip for headlamp relays is NOT to mount them at the front of the car near the actual HLs, far better to mount them back near the bulkhead.

Why? Because if/when you go over a large bump or hump back bridge too enthusistically (sp!), the landing impact can cause the relay to "drop out", leaving you with no lights.

Not fun in a rally car at hmmm mph in Welsh lanes at 2am!!!

[skamanfrank]

Cheers guys
mskinner- thanks very much indeed, just what I needed to know there. Sadly, I'm not near Croydon at the moment- Leeds in fact! But thanks for the offer anyway, very much appreciated