mark_w Posted February 21, 2018 Author Share Posted February 21, 2018 Does only operate manually from the override switch so maybe disabled the fan by choice for extra power . which would be good if everything is in place but just needs locating and reconnecting, feel like I'm getting my head around this a bit now. with what you say Simon checks out with the wiring diagrams the green/blue wire going to the stack via pin 7 on the grey plug which displays the water temp correctly on the stack ..all goodSo the brown plug "talks" to the ecu pin 2 which has on and off temps set but would need to get a laptop connected to verify if they are set up correctly as could have been disabled by choice from here, then looking at this (diagram link) pin 33 rad fan relay drive , is this the output from the ecu to turn the fan on via a relay ? if it is then perhaps a good starting point to tracking the wire to the fan. umm... am i really getting my head around this ? Link to comment Share on other sites More sharing options...
anthonym Posted February 21, 2018 Share Posted February 21, 2018 that all sounds like how I was thinking a few minutes ago, sat in the car with the wiring diagram and having taken a couple of pics... other thoughts are fuse box? relay? have you a standard ecu or emerald? I'll add pics here in a few minutes... edit: thinking about how to disable the fan without denying the ecu the temperature data flow.. set the "fan on parameter" to something extremely high so it never activates, assuming there is no "disable activation" option... and further is this something set within the Stack? If it is it's dead easy to "fix". I'll have a look now, see what I can find in the manual, copy of it is above in my post. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted February 21, 2018 Member Share Posted February 21, 2018 Anthony: have you already got a copy of the wiring diagram for the R500 K with Stack dash?Jonathan Link to comment Share on other sites More sharing options...
anthonym Posted February 21, 2018 Share Posted February 21, 2018 yes courtesy of your good self :-) iirc suggest you add the Stack manual from my post above to your collection. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted February 21, 2018 Member Share Posted February 21, 2018 :-)Jonathan Link to comment Share on other sites More sharing options...
anthonym Posted February 21, 2018 Share Posted February 21, 2018 a mild "duh" moment here, if the Stack dash shows the water temperature, the sensor is working... still reading the manual, can't see anywhere to set the fan activation tempt, only warning temp and of course normal display of temp.. suggests it's ecu activated.. can't help wondering if it's an emerald given the competition use.. assuming it is a Stack.. http://www.emeraldm3d.com/media/software-manuals/Emerald%20K3%20Manual%20v057.pdf extract page 9Main cooling fan control The ECU has a dedicated cooling fan control output that is activated by the engine’s coolant temperature. This 7output switches to earth when active. The cooling fan control output should only be used to switch a relay and not directly wired to the cooling fan motor itself. Having separate ‘On’ and ‘Off’ settings means you can set the temperature at which the cooling fan switches on and also the temperature the engine must cool down to before switching the fan off. The air temperature switch will not be used in most cases, only certain ECU versions will have this function enabled. This function can have various uses, e.g. for switching on a charge cooler when the inlet air temperature reaches a given threshold. To adjust these on/off values press TAB to activate to desired setting and then use the up/down arrow keys to change the setting. Indeed it may be very simple if the relay is under the dash in the fuse bank... disconnect feed to relay from ecu, connect feed from screen switch to that terminal. So from that, easiest way for previous owner to disable the ecu control of the fan is disconnect the connection to the fan from the relay and instead connect that connection to the heated screen switch, while still providing temp data to the ecu and Stack... I'm still looking at this, trying to find the relay, wondering if it is in the MFRU.. apparently not.https://www.lotus7.club/forum/techtalk/rad-fan-relay NO FAN RELAY?https://www.lotus7.club/forum/techtalk/mbe-ecu-0On a mbe ecu, am I right in thinking that pin 16 is for a change up light and pin 33 is for cooling fan relay?the answer was YES Link to comment Share on other sites More sharing options...
mark_w Posted February 21, 2018 Author Share Posted February 21, 2018 standard ecu Anthony , did see your link to the manual so thanks for that Link to comment Share on other sites More sharing options...
anthonym Posted February 21, 2018 Share Posted February 21, 2018 ok, I'm still updating my previous post.. updates there in.. :-) Link to comment Share on other sites More sharing options...
mark_w Posted February 21, 2018 Author Share Posted February 21, 2018 Thanks for all your efforts on this Anthony, looking "here" seems similar to the emerald in that it states goes to a relay to switch the fan on will check out and report back on here Link to comment Share on other sites More sharing options...
anthonym Posted February 21, 2018 Share Posted February 21, 2018 yeah, driving me potty, can't believe there isn't a relay somewhere - excellent diagram, thanks! Link to comment Share on other sites More sharing options...
anthonym Posted February 21, 2018 Share Posted February 21, 2018 and now an updated diagram (thanks Jonathan) which shows a fuse for "Cooling fan" item C 20A. This is different from the diagram I have been working from. So again an easy way for the previous owner to repurpose the screen heater switch would be to swop the power side of the heater switch at its fuse, item H 7.5A fuse, with the power at the cooling fan power side, and it probably wouldn't be that apparent, except the screen heater fuse will be missing its feed.assuming I've got my feeds the right way round... Link to comment Share on other sites More sharing options...
rj Posted February 22, 2018 Share Posted February 22, 2018 Anthony,Won't that diagram be for a Duratec?I haven't read all posts in this thread, but the stock MBE ecu can control the fan. You could as an option get a harness with a relay for this very purpose. Not sure it's available any more, but it's not rocket science.There could be two reasons why the fan does not kick in with the standard thermostat in the top of the radiator:Either the thermostat is faulty or there could be an air lock in the radiator. Until I fitted an external water pump and a remote thermostat my car overheated when I had had a spirited track session. Water temperature went above 100 degrees but the fan didn't kick in because vapor had caused an air lock. Water flow at idle is inadequate for keeping down the temperature. It was not a cooling issue as such as the temperature has always been rock steady when the car was moving (not idling) and adding a huge external fan in the pit did not help. Link to comment Share on other sites More sharing options...
anthonym Posted February 22, 2018 Share Posted February 22, 2018 oh? Jonathan?! (hi rj :-) ) Link to comment Share on other sites More sharing options...
Ian Mackenzie Posted February 22, 2018 Share Posted February 22, 2018 Hi thereI just had a look at this thread....I've got a wring diagram for the r300-500k, PM me your email address and I can email it over. The main thing is that it confirms the pin out of the ECU, but other are correct for the MBE, pin 33 in the fan control, this works by switching to earth, it is not a power supply and needs to switch a relay to earth.My R400 had a relay mounted on the bulkhead to control the fan. If the fan was being controlled by the ECU it must drive a relay, if someone has wired for the ECU to switch the fan directly to earth it is more than likely that the switching transistor will have blown in the ECU and will need replaced. If you have a meter test the continuity to see where pin 33 goes to, does it go directly to the dash switch (this may OK), if it goes directly to the fan and the other side of the fan has +12 with the ignition on (this is wrong and it will have blown the transistor).Regarding the senders in the picture in the thread, once send is the ECU and the other is for the STACK dash.I hope this helps.CheersIan Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted February 22, 2018 Member Share Posted February 22, 2018 Please check Private Mail.Jonathan Link to comment Share on other sites More sharing options...
rj Posted February 22, 2018 Share Posted February 22, 2018 Ian,Spot on. I just didn't remember the pin No on the ECU.What I'd do if I were to wire in the relay was to add the contact in parallel to the radiator thermostat so if one failed there's be kind of redundancy.My own is getting slightly more complex as I am controlling the water pump from a third sensor, but when next generation loom is introduced ECU, radiator thermostat and the third sensor will be able to trigger the fan. Another redundancy is that if the third sensor looses signal, then it'll kick in both water pump and fan if ignition on. Both fan and pump will be enabled with ignition off. Yes, I am a bit paranoid :-o Link to comment Share on other sites More sharing options...
mark_w Posted February 22, 2018 Author Share Posted February 22, 2018 so didn't have a lot of time but managed to trace the pin 33 wire from the ecu to this relay and fuse block on the bulkhead with one wire just cut and hanging free all a bit of a mess so probably would like to try to tidy up and get back to how it would have been wired origionally Must admit i cant find any wire diagram that shows a relay from pin 33 on ecu so was thinking of following this in the guides section on hereecu controlled fan with override switch page 2 Anthony is the fan on your car wired through fuse 3 in the fuse box with a relay there as well ? Link to comment Share on other sites More sharing options...
Ian Mackenzie Posted February 22, 2018 Share Posted February 22, 2018 Yes that is the one, this is also the fuse for the fan on this block.When you switch on the fan from the dash, can you check that the relay is switching....this is a big clue! If you can't decide if it is switching. With the fan off, pull out the relay out then try and switch the fan on with the dash switch, if no longer switches on then we should be a couple of steps away from hopefully fixing your problem....Here is what the wiring should look like: Link to comment Share on other sites More sharing options...
mark_w Posted February 22, 2018 Author Share Posted February 22, 2018 Thanks Ian that diagram shows me what i need to do . will check out if the dash switch goes to the relay suspect not looking at the wire colours. its been done with very thick non auto wire so was wondering what size cable should i use? Link to comment Share on other sites More sharing options...
Ian Mackenzie Posted February 22, 2018 Share Posted February 22, 2018 For the main power feed to the fan I'd use 30amp (My own fan draws over 20 amps but it is a larger unit) and the relay coil wont take much at all so 3amp will be fine.CheersIan Link to comment Share on other sites More sharing options...
anthonym Posted February 22, 2018 Share Posted February 22, 2018 he might have a larger fan too. Clearly I have to go explore my wiring; I have long suspected (in this thread) that relay on the bulkhead may be the one for the fan, but can't find it on the (correct I think R400 for my R500K) wiring diagram. Not sure what state your wiring is in: there is an argument for avoiding a lot of wire distance (a.k.a. vulnerability to faults) that goes from the engine bay, into the cockpit fuse bank and back again in to the engine bay, by having a fuse bank near the ECU. I'm suffering from the wires and connectors slowly degrading with heat soak and age. Tracing which one is today's culprit is time consuming and a pita at the road side. Although fun when the electrics A Team was present at Schloss Dyke last year.and a fuse bank more accessible for anyone over the age of "ooh my back" would be nice. Link to comment Share on other sites More sharing options...
rj Posted February 22, 2018 Share Posted February 22, 2018 Anthony,The R400 MBE wiring diagram and the R500 is the same.The reason this relay is not in the diagram is that it was not fitted from the factory.However, when I wire it in I'll either use a waterproof box under the bonnet or move the whole unit under the scuttle. Electrics in a Seven in general are quite exposed to rain so the design could be ... say... better protected without over-engineering. Link to comment Share on other sites More sharing options...
anthonym Posted February 22, 2018 Share Posted February 22, 2018 aahh.. my car was not factory built, maybe that's why it has the relay on the bulkhead? Now I have to go and look. Link to comment Share on other sites More sharing options...
rj Posted February 22, 2018 Share Posted February 22, 2018 Or someone has upgraded it later on. Link to comment Share on other sites More sharing options...
anthonym Posted February 22, 2018 Share Posted February 22, 2018 no, only that one owner for 18 months iirc before me. Link to comment Share on other sites More sharing options...
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