February 28, 20179 yr 95 Legacy Lsi with 202,000 miles Cooling fans don't come on at all ever. As long as I'm moving air through the radiator (normal driving) there is no problem. I overheat in stop and go summer traffic. Turning the heater on high dissipates the heat somewhat...OEM stat I previously function tested the fans by jumpering from the battery, both worked. Same with the 4 underhood fusebox relays. I plugged the green wires into ECM Test mode and only got the a/c clutch to cycle in and out. No fans. The other day, the a/c clutch kicked in for 20 seconds with the a/c off and defroster on high heat. P0115 error, clears but comes back after awhile. Please, I don't want to hear about hg's,There did seem to be bubbles in the radiator but even if that is the case, as stupid as it may sound, I want to drive that motor until it won't go any further. I just want to know how to make my fan(s) fire short of robbing a powered lead from somewhere.
February 28, 20179 yr The fans are told when to turn on by the coolant temp sensor. If you have a 115, change the temp sensor.
February 28, 20179 yr Author I changed the temp sensor/sender recently chasing another problem (stumbling). That's when I started getting the 115 CEL message.
February 28, 20179 yr There are two coolant temp sensors. If you changed the correct one, you should check to see if there is power at the sensor. Otherwise, you probably need the other sensor as well. One for the engine, one is a fan switch. The one you're looking for is a two wire plug with a single thin probe at the end.
February 28, 20179 yr 95 Legacy is OBD-II compliant. Hook up a scan tool - the fans should come on at coolant temp of 204* F. GD
March 1, 20179 yr Author I changed the 2 wire sensor/sender. On top and back of the engine. Where is the single wire sensor? The temp gets up to the markings at the gauge top and the return bottle is gurgling real good and I'm afraid to let it get a whole lot hotter waiting for the fans to kick on. I'll try it again now and revert.
March 1, 20179 yr Author Well, it got hot enough to blow the radiator bypass tube and the fan never came on.
March 1, 20179 yr It has some kind of issue. You shouldn't be overheating it like that. Spend the $50 on a scan tool so you can know what you are doing and shut it off before meltdown. Remember the lessons from Three Mile Island. Not having a sensor to tell you the water level in the reactor = melted fuel rods and panic in the streets. GD
March 1, 20179 yr Take a good look at the wire harness. Critters seem to like the area around the knock sensor and temp sensors. Like GD said, get a cheap scanner to see what the ECM is thinking the temp is, and whether its commanding the fans on or not. Its interesting though that in test mode they still aren't cycling. Make sure the LF fender liner is OK and road grime hasn't been kicked up at the harness inside the fender.
March 2, 20179 yr Author When I did my amateur fan function test, I undid the fan connector and ran a hot wire from the battery. Upon further review, it appears I didn't get the connector prongs lined up when I plugged it back together. I realized this when I jacked the car up and came face to face with the connector. Specifically the black ground wire looked to be the problem. I lined it up mo better and reinserted the connector and the started the car and, voila, the fan came on with the a/c! Suspecting I may have committed the same error on the other fan connector, upon inspection it looked like I may have buggered it up as well. I lined it up and reinserted the connector and the started the car and, voila, both them fans came on!! And now she idles cool and I get no check engine light. And I was just funnin' about the hg bubbles... It is a miracle...
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