claxton Posted June 12, 2023 Report Share Posted June 12, 2023 Hi all. I have a stag fitted with a Triumph 2.5 engine. With the risk of being shot for being a numpty could somebody tell me what that square shaped thing in the picture is Thanks! Link to comment Share on other sites More sharing options...
Gully Posted June 12, 2023 Report Share Posted June 12, 2023 Looks like a relay to me. Is the dial next to it a clue? Appears to be a fan controller for electric fans? You need to trace the wiring. I'm sure there was a quiz game on TV like this 🤣 Gully Link to comment Share on other sites More sharing options...
JohnD Posted June 12, 2023 Report Share Posted June 12, 2023 It's a relay, Claxton. You need to trace where the wires go to know what it's switching. My gues is that the red wire provides power, which leaves via the green??? when switched by the two other wires, black (earth?) and green (?), so where does the thick green one go? John Link to comment Share on other sites More sharing options...
Colin Lindsay Posted June 12, 2023 Report Share Posted June 12, 2023 I'd agree, it looks to be a relay for an electric fan, the dial looks like a thermostatic controller but it's very far away from the radiator if it's beside the coil. (Maybe it's a converted kitchen timer to cause a delay in the lights going off at night?) Link to comment Share on other sites More sharing options...
claxton Posted June 12, 2023 Author Report Share Posted June 12, 2023 Thanks everybody for replying I take it this isn’t something fitted as standard? Link to comment Share on other sites More sharing options...
dougbgt6 Posted June 12, 2023 Report Share Posted June 12, 2023 Nope! I've replaced my standard Triumph relay with something similar, off a Peugeot if I recall. Doug Link to comment Share on other sites More sharing options...
johny Posted June 12, 2023 Report Share Posted June 12, 2023 That thermostat should have a thin metal tube coming out of it that goes to a hose or fitting on engine or rad? This senses the temperature so the thermostat energises the fan relay at whatever the temperature is set at.... Link to comment Share on other sites More sharing options...
claxton Posted June 12, 2023 Author Report Share Posted June 12, 2023 Hi Johny the relay appears to supply the fan with power via the positive lead on the coil or should I say supplies the thermostat with power which turns the fan on at set temperature. The relay is activated when the ignition is turned on. Seems all a bit unnecessary as power to the coil is cut when the ignition is switched off Link to comment Share on other sites More sharing options...
JohnD Posted June 12, 2023 Report Share Posted June 12, 2023 Claxton, the point of a relay is that it can switch higher currents ( or voltages if that's appropriate) than you might want through a small.dadhboard switch. The fan might draw more current than that. A more typical use is headlamps, or an overdrve, if you have one. Those can draw 30A when going into O/d, although the holding current is much less. John Link to comment Share on other sites More sharing options...
johny Posted June 12, 2023 Report Share Posted June 12, 2023 13 minutes ago, claxton said: Hi Johny the relay appears to supply the fan with power via the positive lead on the coil or should I say supplies the thermostat with power which turns the fan on at set temperature. The relay is activated when the ignition is turned on. Seems all a bit unnecessary as power to the coil is cut when the ignition is switched off Are you sure? Most likely connection should be from ignition through thermostat switch to coil of relay and down to earth. Then a beefy fused supply from battery through relay contacts to fan and down to earth. This is the more reliable set up but means the fan will not run for high temp after the ignition is off... Link to comment Share on other sites More sharing options...
claxton Posted June 12, 2023 Author Report Share Posted June 12, 2023 Yes I am sure it is a dogs dinner. The way the relay is wired seems to make it pointless. Thanks all for your input Link to comment Share on other sites More sharing options...
johny Posted June 12, 2023 Report Share Posted June 12, 2023 An alternative could be: ignition operates the relay coil and then its contacts do a heavier supply to the fan via the thermostat. Thats acceptable as the thermostat is probably rated for the fan current which, most importantly, doesnt come through the ignition... 1 Link to comment Share on other sites More sharing options...
GrahamB Posted June 12, 2023 Report Share Posted June 12, 2023 The wiring is a bit of a mess but it would appear that the relay is operated when the ignition is turned on. The fan will take in the order of 10 amps. Without the relay the extra 10 amps would flow through the ignition wiring and the system is not designed for such a high current. With the relay, the extra current in the ignition system will be less than 1 amp. The current for the fan will then flow direct from the battery through the relay contacts which can cope with upto 30 amps. When the ignition is turned off, the relay will be de-activated and the fan will stop. If the fan is connected directly to the battery, the fan may continue to run after the engine is stopped. The previous owner probably was worried that this continuous draw of 10 amps could flatten the battery, which is no longer being charged by the alternator, making it impossible to restart the engine. 1 1 Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now