Headlight Fuse

[68vitesse]

Just been adding relays to the headlight circuit, as recommended here, on my Vitesse, wondered what the view is of fitting fuse. Options seem don't fit one, fit one in supply to relays and then supply to high and low beam or just supply to relays.

As an aside when shortening and stripping back the old high beam supply, now used to trigger relay, conductor was discoloured and needed cleaning with a bit of emery paper presumably been running a bit hot.

Regards

Paul

[RogerH]

Hi Paul,

fitting the relay thus allowing a better 12V supply to the bulbs is a good idea.

Fuses were not generally fitted originally as they were a mechanical weak link. Indeed they may well blow due to an over load but could well simply just stop working for various reasons.

Today fuses are of better quality and if maintained annually shouldn't cause a problem.

The fact that you could have a fuse going into the relay coil would still give a question mark over it - no different to having a fuse in the power line to the bulb.

If you go for fuses have the offside and nearside bulbs fused separately. That way you will not lose all your lighting at once.

Or have the dip and main fused separately. 

Roger

[68vitesse]

Been reading a bit more and as fuses cause a voltage drop, the smaller the rating of the fuse the bigger the drop, and a fuse is to protect the cable not the load will probably fit the largest fuse for my wiring size.

Thanks for the prompt reply.

Regards

Paul

[Pete Lewis]

be wary of some modern  glass fuses , the old lucas style have a load rating and a blow rating , 17/35 generally a wire fusible

there glass fuses with flat fusibles that just have one rating these can take out old wiring before the fusible lets go 

rated at 30 -35amp and thats  what you get  as a load ,  the blow is much higher   ( so they say ) 

pete

[rlubikey]

When I re-wired and fused mine, I ran separate cables to each headlamp, through separate relays, and each lamp individually fused both switch-side and lamp-side circuits. This way a single failure results in loosing only one headlamp.

Cheers, Richard