fan runs constantly

[achavers]

My daughters 93 Legacy with 200k on it, left radiator fan runs constantly, even when first starting in the morning. The right fan does not come on at all, even when turning on the AC. My suspicion is the the temperature sending unit. Yet, when I look on the radiator, I do not find any temperature sending unit. So, where do I find it. And, is the left fan for cooling, and the right for the AC as my suspicions are? BTW, the car is non turbo, 2WD. She states that her gas milage has gone down significantly.

[Skruyd]

To let you know this should have been posted in the engine forum but it's all good . Just to be sure the left fan is the driver side and the right fan is the passenger. The coolant temperature for the ecu that turns on the fans is on the driver side under the intake. There is a pipe that runs across the block. It has two sensors in it. The one you want is the one that has the two terminals in it, not one. It looks like this.
Image is from DLC.

it could be a relay that is stuck on or off, or hopefully it's not your ecu. But we will leave that as a last resort

[Legacy777]

Sounds like you may have more than one problem. Does the fan run when the key is in the ACC position, or only when in the ON position?

Just for kicks, try unplugging the pressure sensor in the receiver drier on the AC system. That switch serves a couple different functions, one of them is to speed up the fans if the pressure in the AC system gets too high. If that switch is stuck, the fans will keep running, regardless of what the ECU says.

If that doesn't do anything, then yes I'd look at the coolant temp sensor, and or possibly a stuck relay.

There is a little connector/jumper that is located behind the passenger headlight. That should be connected, and causes both fans to come on at the same time. You may want to check that...and also all the fan relays.

[ericem]

Wait josh the pessure sensor plug is the plug near the drier correct?

[Skruyd]

Wait josh the pessure sensor plug is the plug near the drier correct?

It's the switch that is on top of the drier.

[ericem]

Hmm, I need to look again I think I tried unplugging the wrong thing.

[achavers]

So, here is the info you asked for. I just checked to see if the fan comes on in the ACC position and/or ON position, and tonight, it does neither. HOWEVER, there was an incident, and is notable. My daughter called because it would not start at all. So drove to where she was, and, of course the car started right up. She was embarrassed and frustrated. Upon getting it home, it would not start again, but the fan was not running. Let th car sit for an hour, and it started right up.

We drove it around, and stopped at the shop. Stopped the car, turned on the AC, and the left fan kicked on just like it was supposed to. Let it sit and idle for a little bit, without the AC, and the fan started cycling like it is supposed to. Before taking the drive, I had disconnected and reconnected that AC drier.

Anyway, the fan is cycling like it supposed to do.

With that said, it is still only the left fan, and not both fans. That right fan has not kicked in (at least as I have seen it) at all. I thought that if the AC is switched on, that secondary fan (passenger side, BTW), would kick on. And, it is really hot and sticky here in Arkansas right now. It was 92' out there when the car would not start this afternoon.

One last side note. The CEL comes on when you turn on the key (like it is supposed to with all the other dash lights), and then goes off - and stays off. A feat that has not been seen in a long time. Been doing a lot of work on the car in the last six months or so, so it is good to see it finally paying off. It went off, during our drive to leave it at a local shop for a second pair of eyes, but just drove it back home to see what tomorrow holds.

[Legacy777]

Pull the codes and see what is stored in the ECU. Instructions are on my site under notes & tips.

Also, check around the passenger side headlight and look for a little black connector. It'll be connector F2 in this diagram.

http://main.experiencetherave.com/subar ... iagram.pdf

[achavers]

I finally got a chance to get back on the car. Been a series of Murphy events in my life. The codes I got truly concern me.

I got 12, 13, 21, 22. The 21 explains the fan issue. But the knock sensor and the cam sensor concerns me. What do you recommend? Should I clear the codes and then see if it comes back? I know that this thing has strange electrical problems (due to a previous owner being a car stereo nut, and I have had to really clean up a lot of electrical stuff.

[Legacy777]

Yes....clear codes, and see what comes back.