Fan overide mod advice.

[Corin Denton]

Bought another hazard warning light switch from TVR last week to create a manual fan overide in my Chimaera, the intention is to put the button where the stealth button is now and run a circuit from the stereo for illumination when on and then just run an earth to the otter switch.

Has anyone else done this, any tips?

Ta

[dannyboyo]

It depends if the fans are already switched via a relay or not (I can't remember!). If they're not then it means that you'll have the full ampage of both fans (20 or 40 amps??) running through a small switch which will more than likey burn it out.

If the fans are relay controlled, and thats what the otter switch is connected to then I can't see a problem.

Been meaning to get round to doing something like this myself. Last summer I just shorted out the otter switch so the fans were on all summer!!


>> Edited by dannyboyo on Friday 14th May 11:10

[Corin Denton]

Aah, wondered about that - so they just turn off when you switch the ignition off then.

[donatien]

You need to make the switch operate in parallel with the otter. This side operates the relay so only carries small current.

You can probably get some piggy back spade terminals - put these on the otter, put the original otter switch leads back on and run new wires off the connectors to the switch.

Dave

[dannyboyo]

Corin Denton said:

Aah, wondered about that - so they just turn off when you switch the ignition off then.

That's right. I found that if the fans is switched on straight away in the hot summer (or before the car gets to 70/80C) then it's easier to keep it low. Once the car gets to 90/95C it's unlikely that the fans will be able to get the temp back down again.

For summer use, easiest just keep it on all the time, they're not too noisy. And unlike other cars, they do switch off when the ignition is turned off too.

Just gets a bit stuffy in the drivers seat!!

[wedg1e]

The fans should be (even by TVRs methods) switched by a relay. ID the relay, find the incoming wire from the Otter switch and connect your dash switch to it (other side of the switch to ground - at least on my car!). THEN snip the positive feed to that relay COIL (which is ignition switched ) and re-route to a permanent 12V feed. This allows the fans to stay on after you switch off.
If you must have an LED, you really ought to connect it directly to the fan, as there's nothing to tell you whether the wires have fallen off the relay...

Ian

[chimburt]

consider fitting some heavy duty cable ( 30 - 40A ) and an additional relay per fan. they go like the clappers if they are run from a decent supply ( such as the connector just ahead of the drivers feet underneath the car, which is straight onto the battery, and there's an earth point nearby too. ), a relay to cope is peanuts ( use an auxilary driving lamps relay from halfords for instance ) and you can leave the existing wiring in place to switch your new relays. for god's sake fuse each fan individually. i used 30A for mine, as let's face it, if the fan's knackered it's knackered, and a couple of extra amps won't make much difference for the short period of time it would be drawn. run the new feed through the relays to each fan. if you have an otter switch which is standard ( 84C i think ) then the increase in fan speed should be enough to handle the heat in the rad.
spend a tenner now and you'll also save buying those heavy duty fusues at £2 a pop or whatever, not to mention pratting about with the ecu and the fuse board.
fan over-ride still useful for those otter switch moments though