Bullitt Posted March 6, 2009 Share Posted March 6, 2009 Hi, I want to fit such a switch. Is there a shopping list for the things which I would need - switch, relay, resistor and LED? Charly Edited by - bullitt on 6 Mar 2009 10:15:24 Link to comment Share on other sites More sharing options...
Miltec Posted March 6, 2009 Share Posted March 6, 2009 Just done this 1: A Switch 2: Some Wire 3: LED err that's it really, give me a shout if you need any help VX 1600 Live Axle T440LKK rFactor: caterham.miltec.biz Link to comment Share on other sites More sharing options...
alextangent Posted March 6, 2009 Share Posted March 6, 2009 Wire, rated at whatever the fan draws on startup; I used 15amp. I did this last year, but without the LED, on my xflow. The easiest route for me was to run a wire from the positive side of the thermostat switch to a relay under the dash.Then a positive feed from the ignition (position 2 so the fan goes off when the ignition is off) to the switch and then to the relay. The relay wiring is set up so that when the switch in ON, it energises the relay coil, and the same positive feed is used across the relay switch. I used the common earth point under the dash for the other side of the relay coil. It's actually easier to do than describe, and I think there may be a diagram out on the intertubes or somewhere here on BC. Alex McDonald Loud, louder, loudest... Link to comment Share on other sites More sharing options...
Graham Sewell Posted March 6, 2009 Share Posted March 6, 2009 I located the relay inside the engine bay near the radiator to minimise the 12V runs. I then piggybacked the switched circuit onto the existing switch and also piggy backed the live feed on the relay from the lived side of the switched circuit on the relay. Then all that was needed was a switched earth lead from the earth side of the relay to a switch on the dashboard which feeds into the earth loom. This means that if anything goes wrong, it is only a low voltage, low current wire running back to the dashboard. Cheers, Graham ------ Low tech luddite - xflow and proud! Link to comment Share on other sites More sharing options...
alextangent Posted March 6, 2009 Share Posted March 6, 2009 Did you use some ruggedised relay? I would have thought that water ingress would do the relay in pretty quickly in the engine bay? Alex McDonald Loud, louder, loudest... Link to comment Share on other sites More sharing options...
Bullitt Posted March 6, 2009 Author Share Posted March 6, 2009 Thanks. I have found some postings here in bc and THIS very useful scheme. But it would be very helpful to know what kind of exactly parts (switch, relay, resistor, LED) you have installed Link to comment Share on other sites More sharing options...
Graham Sewell Posted March 6, 2009 Share Posted March 6, 2009 I used a switch like SW9 and a relay like R20B. The cable was Ref 20 in a selection of colours (Black/Green for the relay to fan switch - switched side, Green for the relay to fan switch live and Black for the relay to switch (Earth)). Cheers Graham Cheers, Graham ------ Low tech luddite - xflow and proud! Link to comment Share on other sites More sharing options...
Graham Perry Posted March 6, 2009 Share Posted March 6, 2009 I ordered the Caterham heater fan switch as it matched all the others and there was just about enough space to fit it on the dash. Link to comment Share on other sites More sharing options...
Bricol Posted March 6, 2009 Share Posted March 6, 2009 Why not simply fit a working fan switch? If it's toast, then you can guarantee you'll forget to switch manually . . . until you notice the steam. Bri Link to comment Share on other sites More sharing options...
alextangent Posted March 6, 2009 Share Posted March 6, 2009 Coz us xflow boys don't like sitting in traffic. For some reason best know to someone other than me, the thermostat switch always seems to kick in far too hot. The thermostat is a 74deg, but my fan doesn't come on until around 10deg higher. Hence the switch on the dash. Alex McDonald Loud, louder, loudest... Link to comment Share on other sites More sharing options...
Bricol Posted March 6, 2009 Share Posted March 6, 2009 But that sounds okay to me. Fans are supposed to come in higher than stat temp. Never had a problem with my crossflow with a switch in the stat housing. It's not even a problem with a crossflowed Dutton we use for trialling - lots of revs, via really low first gear, and a really low diff (combined 20:1), moving slow, usually caked in mud. Bri Link to comment Share on other sites More sharing options...
Bullitt Posted March 8, 2009 Author Share Posted March 8, 2009 Thanks Graham S. That helps Regards, Charly Link to comment Share on other sites More sharing options...
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