Adding new circuits to the fuse box

[stevie_b]

Has anyone used the unused fuse slots in the fusebox to run extra electrical circuits to power things (e.g. airhorn)? Some of the unused slots have the battery-side electrical contact present, but no contact for the other blade of the fuse.

[merckx]

I haven't yet, but someone on Supraforums used the one for the heated front seated which he didn't have fitted.

 

When I did the airhorn on my van I used the existing horn power supply to switch a relay , the power for the airhorn came directly from the battery and through the relay.

[stevie_b]

When I did the airhorn on my van I used the existing horn power supply to switch a relay ...

 

Yep, agree with that.

 

.... the power for the airhorn came directly from the battery and through the relay.

 

Via an inline fuse, I presume? Otherwise if the high-power feed to the relay were to touch the bodywork, it would create a short. Did you take power directly from the +ve terminal of the battery?

[Sheefa]

I fitted my airhorn a while ago but am having problems.

 

It did come with a relay, but said it probably wasn't necessary.

 

I've hooked mine up using the existing spade connection and grounded the horn to a chassis bolt. However, it does keep shorting. I've blown about 7 15amp fuses so far, but I think it's down to the ground wiring as I'm using some unknown wattage.

 

Got some 17amp black wiring that I'm now going to hook up to the neg batt terminal which should 'hopefully' sort it.

[merckx]

Via an inline fuse, I presume? Otherwise if the high-power feed to the relay were to touch the bodywork, it would create a short. Did you take power directly from the +ve terminal of the battery?

Yes to everything!

[stevie_b]

I fitted my airhorn a while ago but am having problems.

 

It did come with a relay, but said it probably wasn't necessary.

 

I've hooked mine up using the existing spade connection and grounded the horn to a chassis bolt. However, it does keep shorting. I've blown about 7 15amp fuses so far, but I think it's down to the ground wiring as I'm using some unknown wattage.

 

Got some 17amp black wiring that I'm now going to hook up to the neg batt terminal which should 'hopefully' sort it.

 

Hi Sheefa!

 

I've got my airhorn working, but I just want to wire it up at the battery in a neater way. I got mine from Halfrauds.

 

I've used the existing horn wiring to act as the "signal" to the relay to activate it. The stock electrical horns take much less current than an airhorn, so it's unwise to use the existing wire to try and power the airhorn. What I've done is got an inline fuse run a high-current wire from the battery via an inline fuse (30amp, I think, fitted as close to the battery as possible) to one of the inputs of the relay. Like you, I've grounded my horn using the chassis bolt that the old horn used.

 

My guess is, I don't think you've got a short, I think you're just drawing too much current for the fuse to cope with. The horn's air compressor is a thirsty beast!

 

Oh yeah, make the grounding wire that goes to the -ve battery or chassis point as high-current as possible. 17amp doesn't sound heavy duty enough for this. I would look for 30amp. Remember, the high current from the compressor AND the signal current from the horn switch will both be flowing through this bit of wire. If you want photos or more advice about how I've done it, just give me a shout.