Radiator fans not coming on

L

LucasJ

New Member
Hi,

I recently did a 4g15 - 4g93 swap in my 2000 ce lancer. Everything works fine except for the radiator fans, they don't seem to come on even when the car warms up, they only come on when I turn the A/C on.

I have bleed the coolant properly, I have replaced the coolant temp sensor, water pump and thermostat, if the fans themselves work when a/c is on it can't be a wiring issue (I don't think). I have also noticed my temp gauge sits at just below half which from what I've researched means its too cold for the fans to come on, but I've driven the car for over an hour in aussie summer heat and the gauge never goes above half.

I haven't had any overheating issues yet but I can tell pretty obviously the engine is very hot, and I can smell a bit of burnt coolant from the engine bay after a drive. Oh and no coolant leaks or anything like that either.

Any help would be hugely appreciated, sorry if this has been posted before, i couldn't find any posts about this specific issue. (I don't want to cook brand new engine :O)
 
Let the engine warm up idling till the temp gauge goes above half and see what happens. Do you have a good heater? It can take 10 or 15 minutes to get up to temp just idling and when driven above 40kmh the air passing through the radiator cools the engine. Fans don't really have much affect above that speed.
 
I've done that, let it idle for a while (20mins or so) and still nothing. Heater works fine sorta. I've noticed there isnt much coming out of the air vents inside the car even when blower is on max. So not sure if that affects it or not, I just assumed they might've got clogged.

And yeah like I said the temp gauge will not go above just below half no matter how long I idle it or drive it.
 
Drive it then up to temp turn heater off then let idle till it overheats or turns fans on. It will only run one fan and it will be fairly quiet.
 
Had the same problem on my Proton Wira long time ago;
4G15 uses a thermo switch on the radiator to turn the fans on (check on the small old radiator).
Most 4G93 turn the fans on from the ECU (sends ground to activate the fan relay in the engine bay), so I suspect that's your problem - check and report. How many yellow connectors do you have on your ECU - 3 or 4?
 
I have 4 yellow connectors on the ecu, is there a secondary relay I need that the 4g93 has but the 4g15 doesn't? I checked the fan relay in the fuse box and its fine.

Another thing, when I unplug the coolant temp sensor the fans come on. The car idles weird and the fans stay on forever so I'm not gonna leave it unplugged, so Im assuming the ecu has a fail safe mode if its not receiving a reading from the CTS and just automatically turns the fans on.
 
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