View Full Version : Cooling Fans not kicking in

22-08-2018, 06:54 PM
Hey guys, on my 91 N14 SSS SR20DE the fans don't kick on at all. I've done testing too find the problem first started by checking the fuses(all good), then checked for power with a multimeter on the relay connector terminals for the fans and they have power, the fans do turn on with a wire linked, then put it all back together to check if I could turn the fans on via the consult port using a computer and they turn on with that which means the relay is good.

A few months ago when I did have the same issue I checked the relay connector terminals for the resistor on the relay which one side is the battery which always has power and the other is from the ecu when testing this I didn't get power across the terminals until the fan kick on temp was reached(82 - 88c) which meant all was good so I replaced the relay and all went back to normal. Now when I test the same thermals in the same way I don't get power at all! I've even left the engine idle until it hit 95c with the the relay and without and still nothing. Also to mention while the consult port says its about 95c, which would normally be overheating the gauge says its fine and sits in the middle and doesn't move unless warming up and only sometimes but rarely in traffic the gauge will go up and then down and repeats so I think the fans are on so I pull over and have a look and they're not on!

I have no clue what it could be, maybe a broken wire, bad temp sensor and gauge sender. I also can't test the temp sensor because I can't get the plug off which has the u clip on it. Also to mention I recently replaced the water pump on the engine possibly because of overheating but again I have no clue. Hope someone can help me who knows what to check or if they had this problem before and fixed it. Thanks Corey

23-08-2018, 01:39 PM
100degC is the kick on temp for thermofans for a DE. Brings down to 95degC then off. DET is on at 95, off at 90degC. This is normal operation. Coolant mix under pressure shouldn't 'boil' until at LEAST 110degC with a proper mix.

23-08-2018, 01:41 PM
IF you bled the system properly, you should notice the "cold" level of the coolant bottle each morning is the same. It will rise as the car heats up, but should always fall to the same level. If you're having to top it up, then it hasn't been bled properly.