Discussion
My fan wiring is certainly not original, and doesn't look so good, I have a cable coming direct from the battery terminal to the positive of the relay coil, the relay is just hanging near the fuse box, the supply to the contacts is powered from 2 small cables connected in parallel via a hanging 40A fuse holder fed from a new cable connected to the live side of the 80A fuse from the battery, the switched contact then feeds out on 3 cables, 2 to one fan and one to the other.
The strange thing is that fans only work with the ignition on, this must mean that the coil negative must be switched by the ignition.
I would like to tidy all this up, I guess I can refit the fuse and relay into the dash area, what size cable should I use and are spade connectors good enough for these higher amp circuits, both of my fuse connectors and the one supplying the relay look like this
One last question, what is best to cover the cables that will run through the engine bay to protect them from the heat and elements?
Thanks
Paul
The strange thing is that fans only work with the ignition on, this must mean that the coil negative must be switched by the ignition.
I would like to tidy all this up, I guess I can refit the fuse and relay into the dash area, what size cable should I use and are spade connectors good enough for these higher amp circuits, both of my fuse connectors and the one supplying the relay look like this
One last question, what is best to cover the cables that will run through the engine bay to protect them from the heat and elements?
Thanks
Paul
Edited by Paulprior on Monday 21st November 21:03
If i were to rewire the fans id probably use 2 circuits, if one fan were to go down or blow a fuse the other could still operate.
You would need a rough idea of the fans rating in watts to calculate the current draw, im guessing they are about 15 Amps each? maybe someone can confirm.
If this was the case you would need cable suitable of carrying 30 Amps comfortably, you always should oversize cable slightly for safety reasons.
This is an example of course based on 30 Amps but looking below a cable of 4mm would be ok but personally id step it up to 6mm for belt and braces.
http://www.12voltplanet.co.uk/single-core-plain-co...
Running two circuits would obviously require two relays etc but these are not exspensive.
nylon sleeving is usually enough protection for areas not too close to manifolds etc.
http://www.12voltplanet.co.uk/split-convoluted-sle...
Im not sure how Tvr wired the fan circuit but would guess the otter switch is responsible for switching the relay.
You would need a rough idea of the fans rating in watts to calculate the current draw, im guessing they are about 15 Amps each? maybe someone can confirm.
If this was the case you would need cable suitable of carrying 30 Amps comfortably, you always should oversize cable slightly for safety reasons.
This is an example of course based on 30 Amps but looking below a cable of 4mm would be ok but personally id step it up to 6mm for belt and braces.
http://www.12voltplanet.co.uk/single-core-plain-co...
Running two circuits would obviously require two relays etc but these are not exspensive.
nylon sleeving is usually enough protection for areas not too close to manifolds etc.
http://www.12voltplanet.co.uk/split-convoluted-sle...
Im not sure how Tvr wired the fan circuit but would guess the otter switch is responsible for switching the relay.
Thanks for the links, if someone could confirm 15A then I could use 2 or 3mm, a separate fuse each sounds a good idea, but maybe stick to 1 40A relay, I just need to find how to route those cables, they don't look to appear anywhere on the upper side so must be routed down below somewhere.
Yes the otter switch switches the relay, but on mine the otter switch is supplied directly from the battery and then back to the relay, but the fans only work with the ignition on, I think I will use the dash light button to override the otter switch, and as someone recommended I could connect that to the unused red light at the bottom of the Rev counter.
Yes the otter switch switches the relay, but on mine the otter switch is supplied directly from the battery and then back to the relay, but the fans only work with the ignition on, I think I will use the dash light button to override the otter switch, and as someone recommended I could connect that to the unused red light at the bottom of the Rev counter.
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