Haavard Guttormsen Posted January 16, 2009 Share Posted January 16, 2009 Does anyone know how the AC / engine electric fan should work? Is it supposed to run only when AC is enabled? My setup is as follows: TD5 EU3 engine and auto gearbox in a RRC. I do not have AC system up yet. It won't be connected until the summer gets back here in Norway. I don't have the viscous fan installed because it was destruceted when the car then engine came from crashed. I have just started the engine and have not driven it yet so I really do not know how the fan should work. I can make a paralell feed to the fan relay from a temparature switch but it would be best to leave it as controlled from the ECU. Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted January 17, 2009 Share Posted January 17, 2009 Yes, the aircon fan is controlled by the ECU because if you overheat the engine (or the ECU thinks you have) it sets a fault in the ECU which causes the aircon fan to run constantly with the ignition on. We often have to reset this error with the computer to stop the fans running all the time. Quote Link to comment Share on other sites More sharing options...
M&S Posted January 17, 2009 Share Posted January 17, 2009 Yes, the aircon fan is controlled by the ECU because if you overheat the engine (or the ECU thinks you have) it sets a fault in the ECU which causes the aircon fan to run constantly with the ignition on. We often have to reset this error with the computer to stop the fans running all the time. This is useful to know. Jim, can I just clarify that the AC fan only normally runs when the AC is on and when needed (so not if the AC was on but it was -2'C outside)? Cheers, Martin Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted January 17, 2009 Share Posted January 17, 2009 I think the a/c fan runs when the a/c is on no matter what the outside air temperature is. But I could be wrong... Doubtless someone more knowledgeable will be along soon to answer this Quote Link to comment Share on other sites More sharing options...
teabag Posted January 17, 2009 Share Posted January 17, 2009 I sometimes have the a/c on with the heater turned to hot to demist the inside a bit like climate control ie. a/c air blended with hot air. Could be -10 outside as it has been in the UK recently, that would not cause any problem . Quote Link to comment Share on other sites More sharing options...
Haavard Guttormsen Posted January 18, 2009 Author Share Posted January 18, 2009 I will try to give an input on the AC request input on the ECU today. I have not ran the engine up to more than 40 degrees yet. Then I will see if the fan starts as soon as I connects the AC req. input. It will probably start immediately then. Quote Link to comment Share on other sites More sharing options...
Haavard Guttormsen Posted January 21, 2009 Author Share Posted January 21, 2009 Tested the AC fan request wire today. As soon as You ground it the fan will start. I think I will just add a thermostat that grounds this wire. Quote Link to comment Share on other sites More sharing options...
M&S Posted January 21, 2009 Share Posted January 21, 2009 Handy to know, cheers. Quote Link to comment Share on other sites More sharing options...
Haavard Guttormsen Posted January 21, 2009 Author Share Posted January 21, 2009 Is there anyone who knows which temparature the viscous fan is supposed to start working at? I can not find it in the Rave manual. Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted January 22, 2009 Share Posted January 22, 2009 The Rave manual, as you know, tells you how the viscous fan works, or how it is supposed to work. It does not tell you how to test it or at what temperature it is supposed to lock up. In the workshop, we work on the following: If the fan is locked solid or freewheels then it is no good If there is fluid on the front of the fan where the coiled spring is, then it is time to change it. If the owner complains about overheating we will often change it, and it is normally the culprit. If it doesn't fix the problem, then we put the old one back and look for something else. On the TD5 you can hear the fan 'kick in'; not on the Tdi engine though. Quote Link to comment Share on other sites More sharing options...
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