Horn And Full Beam Don't Work

[Guest A.B]

Just getting the car together ready for an mot and I've noticed the horn nor the full beam work. Are they on the same fuse?

 

I couldn't see any of the coloured ones out but I'm unsure about the large ones.

 

Flash full beam still works along with everything else.

 

Any guidance would be really appreciated!

[alanrichey]

They are on my Superspec. It was one of 4 in a Fuse holder. I suspect yours are different so it's just a case of checking each one.

[Guest A.B]

I can't seem to see anything blown, I've got a few in line fuses but they seem ok.

 

My build wiring built diagram isn't the best so could it be one of the three big black fuses or would more things be out in that case?

[Bob Tucker]

They should both be on relays.

[philshelton]

as bob said should be on relays. could be a bad earth on the low current side of the relays if its not a fuse. bad connection at the stalks, sorry to say it is a case of working your way through things, if things have been done well then it should not be too hard if you have a bird nest of wires behind the dash then it could be a right pain. If the latter if the case I would put rewire at the top of your winter mods list

[sj-bradley]

Are you sure the three "big black things" aren't relays ?

 

I've never seen black fuses yet. (except blown ones)

 

Simon.

[Guest A.B]

Sorry guys for the late reply. I've been working away a lot and haven't had any time for the car sadly! The big black things are relays. How do I go about testing them? Is that the best place to start? I'm also starting to think I have a bad neutral to the fuel pump after I repositioned it on the body, I take it a can just run a neutral cable to the fuel pump rather than just using the body for a better connection?

 

Really appreciate any guidance.

[agent_zed]

you can normally hear the relay click on. It won't be very loud but normally audible.

 

Just to check right back to basics ....

 

Take the horn push off and manually bridge the wires as it could just be the horn push (switch).

was about to say check your bulbs but re-read and you said flash was working so we know they are good. So in theory the bulb and wires from the lights to the relay are good. Everything past that point is where you should be looking. So it will either be the relay/stalk/ or wiring in between.

 

you could try a multimeter on the stalk terminals if you can work out which wire it is. You can then tell if you have 12v before the switch and if you have 12v after i.e. if you switch isn't working. If you have 12v after the switch it must be the relay or wiring to the relay.

 

hopefully my thinking is correct and makes sense

 

hth

[Guest Gargoil]

You could just do a temporary job with the negative to the fuel pump, just to prove the fault. If it does prove to be the problem then you could make it more permanent but finding a better chassis earth would be better and easier.

[Guest A.B]

The car had fuel pick up problems when I bought it so I replaced everything and it was picking up fuel fine then I moved the position of the fuel pump. I had to change the position after changing to braided hoses and areo fittings and that section of the body doesn't seem to have a good neutral. When I move it back to its original position only 3 inches differece still vertical it picks up so my initial thoughts was the neutral?

 

The lights work on dip but don't flash. The dash wiring isn't bad at all. I belive there's two or three relays. So shall I work from stalk to relay?

 

Thanks guys

[agent_zed]

so there is no main beam at all? first of all check the bulbs. Sounds silly but far easier than spending hours wire chasing only to find it was the bulbs.

 

can you hear the relay click at all when you switch to full beam?

[Guest A.B]

Sorry I've written that the wrong way round. The flash / full beam work. The dipped driving lights don't work. Is it all through the one bulb. It looks like it but I haven't taken the unit apart.

 

Unsure about the click on switching to full beam. I'll check it over the weekend.

[Bob Tucker]

Not well up with electrics, but mine has separate relays for dip & main.

Try swapping them over & see if the fault moves with it.

[agent_zed]

ah ok. well either way check the bulbs. They are likely to be 'sealed beam' units where the bulb is the whole light.

 

where roughly in gloucestershire are you?

[Guest A.B]

I'm in tewkesbury. I'll have a look at the weekend and give you all some updates. I take it the relays are interchangeable? I won't blow one if I swap it incorrectly?