Fitting cooling fan override

[BIGMIKE1]

What do people suggest for the easiest way on fitting a fan override? I was thinking just twin cable run back from the otter switch and using the dash illumination switch or can I pick the wires up near the fuse box easily as that would be neater?
Would you bother with a relay or just use the dash switch?
Mike

[SILICONEKID343HP]

I have a heavy duty switch under the steering wheel then ran a heavy cable to the Otter switch .

[miniman]

Elegant solution is to use the rear wiper switch from the Vauxhall column stalk, via a relay.

[carsy]

BIGMIKE1 said:

What do people suggest for the easiest way on fitting a fan override? I was thinking just twin cable run back from the otter switch and using the dash illumination switch or can I pick the wires up near the fuse box easily as that would be neater?
Would you bother with a relay or just use the dash switch?
Mike

Exactly this. Two wires piggy backed on to the otter connections and then the other end of the wires attached to any old switch and locate it anywhere convenient.

[David Beer]

Of course you should have compete faith in the cooling system so do not require an override if you do need one a piggyback from the otter is easiest
It does not have to be heavy duty, It is only.rated at around 200 milli amps . You can modify the relay so no
need to run wires to the otter.

[BIGMIKE1]

Cheers guys its only as a fail safe after the otter switch failed when we were sat in traffic for nearly an hour the other week.

[Harrytsg]

I use the mod wise 2 stage fan controller, it has 2 controls you can adjust, first for half speed , second for full speed. Mine rarely gets to full speed nowadays.
If this unit fails, then the otter sw is the back up.
I also fitted a led, facing me in the lip of the bonnet to show when the fans are running.

[spend]

Just look for a green/pink wire and switch it to ground. It is all over the dash & fuse box area, easiest point normally to splice into it will be near the 50odd way engine connector behind the radio / bulkhead grommet (as its closest to where you want the switch).

[EGB]

Previous owner already done this when I discovered his hidden switch under steering wheel binacle. I therefore used my direct wiring to the otter via under the right wing, for a green LED on the binacle. This comes on green when otter is triggered to switch on the fans. Tells otter and fans are working ok in slow/stop heavy traffic.

See green binacle LED and hidden discovered position of fan over ride switch, see arrow.

[David Beer]

I guess you can not see the led if you are in a straight line! Quinny had two leds one for half speed and one for full speed i only have the one

[EGB]

Agreed David. Well observed. No problem for me in practice, I'm tall enough to see or a quick twiddle, but not on bends!. It works ok on slow bendy roads on hot days. On straight ahead at 70+ with rad cooling, no worries. LED best put above oil pressure LED but my brittle facia trim may fall to bits in the process. Needs to be done sometime.

Edited by EGB on Friday 5th July 22:03

[s p a c e m a n]

spend said:

Just look for a green/pink wire and switch it to ground. It is all over the dash & fuse box area, easiest point normally to splice into it will be near the 50odd way engine connector behind the radio / bulkhead grommet (as its closest to where you want the switch).

This is the way that I would prefer to do it, but looking at the bible it is telling me that green/pink is choke solenoid to choke switch, black/orange is the only mention that I can see of fans and thermal switch. I know that the wiring is as random as the winning lottery numbers, but is anyone able to give me more of a clue of what I am aiming for?

[Ozstyle]

Spaceman,
the otter switch wire is green/pink, the wiring diagram in the bible is correct, ignore the british standard list, doubt TVR used it.
I have just fitted a fan override switch to my Griffith. Just after where the main loom enters the cabin there is a translucent white connector (about 24 pin). One side has the Range Rover loom colours, the other side connects to the TVR dash wiring loom, this side has the green/pink wire. I poked a wire into the back of the green/pink connector pin, turned on the ignition and earthed the wire to check the fans came on (they did). I spliced a new wire into the green/pink wire, ran it across the main loom to the steering wheel cowling. Connected it to a rocker switch I fitted in the cowling, earthed the other side of the rocker switch via the steering column mounting bolt which already had a black earth wire fitted to it.
Oz

[Harrytsg]

I believe you can utilise the wiper stalk rear wipe function (push forward) as a switch for this instead of installing an extra switch.

[s p a c e m a n]

Top man Ozstyle that is exactly what I was after, half of the job would have been poking around trying to figure it out so you've helped me get out earlier to enjoy the sunshine

I'm going to see if I can find a bulb holder and then wire up a light to go into that spare at the bottom of the rev counter, peace of mind for when I've got a helmet on and can hear sod all.

[RochdaleGT]

BIGMIKE1 said:

Cheers guys its only as a fail safe after the otter switch failed when we were sat in traffic for nearly an hour the other week.

did any production car (classic or modern) ever came from the factory with an override?
how many times in a lifespan of a car does a quality otter switch fail?


so the conclusion in installing an override should be clear now?

[s p a c e m a n]

RochdaleGT said:

BIGMIKE1 said:

Cheers guys its only as a fail safe after the otter switch failed when we were sat in traffic for nearly an hour the other week.

did any production car (classic or modern) ever came from the factory with an override?
how many times in a lifespan of a car does a quality otter switch fail?


so the conclusion in installing an override should be clear now?

Because 15 year old TVR.

It's not just an otter switch override, it's a failsafe test for the connections/fuses/wiring and anything else in the system. You're looking at the gauge thinking that it's a bit high, you can either flick a switch and know instantly whether the fans are still working or you can wait and then make a quick scramble to override it if they're not.

I've fitted one to a few of my cars when I thought that it warranted it, I'm mainly doing it now so that I can also put a light in and know they're working when I have a helmet on

[SILICONEKID343HP]

s p a c e m a n said:

Because 15 year old TVR.

It's not just an otter switch override, it's a failsafe test for the connections/fuses/wiring and anything else in the system. You're looking at the gauge thinking that it's a bit high, you can either flick a switch and know instantly whether the fans are still working or you can wait and then make a quick scramble to override it if they're not.

I've fitted one to a few of my cars when I thought that it warranted it, I'm mainly doing it now so that I can also put a light in and know they're working when I have a helmet on

Just fit one spaceman ,I have one, just a simple switch under the dash with a heavy duty cable neatly tie wrapped to the chassis in the engine bay ..

[s p a c e m a n]

I'm half way through it, I need some supplies to finish it though so I'm buying more random ebay rubbish