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97 GT cooling fans on all the time


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OK fellas, I have to admit that I'm stumped.

 

I bought a 97 legacy GT sedan (230k and 4eat) with a blown motor because I had a 2.2 that needed a new home. The car had been sitting in a lot for about 8 months with a rod poking out of the top of the case. When the tow driver put the jump box on the battery to get the car in neutral, the fans kicked on. Both of them, on high. When he went to unload the car, the same thing happened. As soon as the key went to ACC, they both roared to life.

 

I stuffed in the 2.2 and it started right up, BUT those darn fans are still kicking on as soon as the key hits ACC. I've replaced all the A/C relays under the hood and all the wires going to the relays are plugged into them. Both of the ECT sensors were also replaced. There are no check engine codes. (the AT temp light does the 16 blinks of death at start-up, and even though I don't think it's related, who knows? I tried pulling TCU codes with the 5 pin jumped and the whole gear selector dance, but couldn't get anything out of it.) Oh, there is also a Clifford alarm installed but isn't connected. It's looks to me to be professionally mounted, but was obviously disconnected from power many moons ago.

 

In the morning I'll plug the scanner in and check the temp reading from the ECU just to make sure. These things are making me crazy! Anyone have any ideas?

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Do they stay on or cycle on and off?

 

Check under the dash for the green test mode plugs and make sure they are UNplugged. There may be a set of black connectors as well which should also be UNplugged.

 

Other than that, temp sensor wiring could be shorted, or the ECU may be bad.

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Both the test connectors are unplugged. I was going to plug the scanner in tomorrow to see what the ecu sees as far as temp. I was hoping to watch it rise on the live stream until it hits operating temp but now I'm not sure what I'm hoping for.

 

The harness was changed with the engine so any break in the circuit will likely be a PITA to chase but I think I've used up all of the easy options...

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You took the harness from the EJ25 engine and installed it on the Ej22 engine or you used the Ej22 harness?  

 

I have seen a rod come up thru the coolant crossover pipe and crack it and it wouldn't be hard to crack a part of the coolant temp sensor as well.  

 

Happy to take a peek at it if you want to stop by my shop.  Details at retroroo.com 

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So here's a thought... Since I can't seem to get codes out of the TCU, do you guys think the fans could be on if the trans temp sensor is malfunctioning and reading hot?

 

This is what I did to try and pull codes-

 

Located the black plug under the dash and put a grounding pin in #5 with the key out of the ignition.

 

Turned KOEO and waited for flashes. Nothing.

 

Tried the other grounding pin with the same steps and nothing.

 

Ohmed the pins to chassis and they're both good grounds.

 

Tried again but this time started the engine. 16 flashes then nothing.

 

Am I missing something? I also tried the secret handshake about a half-dozen times for fun but didn't get anything.

 

My next thought is that some genius may have hard wired the fans to switched B+ because they weren't kicking on so I'll see if I can spot any splicing.

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The temp gauge on the dash is reading below half, which is normal if my herd of other Subies is any indicator.  And I watched the temp steadily climb from cold start this morning on the "live data" setting of my scanner until I hit 180 and decided that I had seen enough to know that the ECT was sending good data to the ECM. And there are still no trouble codes, either. Hmmm...

 

So I have a new (and... desperate?) thought. if YOU were going to hard wire the fans to come on every time you turned the key, where would YOU do it? I can do mechanical stuff all day long but the electrical stuff doesn't come naturally to me. If I had wired the fans to constantly run and then posted the pictures on here, EVERYONE would have a good laugh!

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Oh there are so many places where the cooling fan circuit can be messed with and make the fans kick on. You're gonna need a wiring diagram for this one.

Check here: http://www.main.experiencetherave.com/subaru_manual_scans/ for a FSM for 97.

 

Basically, the fans should not have power unless the main fan relays are being grounded by the ECU. If pulling the relays out makes the fans turn off, then the circuits between the relays and fans are Ok. The next thing to check would be the ground wires for the control side of the relays at the ECU.

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It almost seems like the PCM is fried....but I can't really say if it is without being there...the only reason why I was that is that is because you are getting a good (or so I think) reading to your PCM (because your scan tool is picking it up)... and a good reading to your gauge....put your fans are staying on and you are having other lights come on your dash....If I recall though the gauge should be about half way, and it should run at about 190 degrees or so...One other thing you could check is your electric fan relay to see if is stuck on, then if that fixes the fans go from there about the other issues 

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Thanks for the ideas guys. I'll pull the relays and see what happens. At least it'll narrow my searching if nothing else!

 

I think I left out some important info on this thing. When we (my son and I, it's his project) went to pull the motor, everything had the wrong fastener in it. And I don't mean the bolts were mixed up, I mean the majority of them were SAE with 10 years of rust on them. One of the fans had a single bolt and duct tape holding it on. About half of the bolts on the timing cover were snapped. What little coolant was left was Dex-cool.We bought the car from a kid who had been driving the crap out of it.

 

It did, however, have brand new heads, and brand new timing belt, and new idlers. My theory is that this kid had his timing belt snap and it smashed all the valves. He got new heads and a timing set and slapped them on. He, or his friends, kind of rigged the car back together and started driving it like a race car. Then punched a rod through the block on the interstate and said screw it. This is why I think the that a relay went bad (they have all since been replaced) and the fans were just wired to run all the time. 

 

I think the transfer solenoid is truly an issue. The torque bind isn't as obvious as a fire truck coming at you, but I've felt it enough times to see the writing on the wall. Why I can't get the codes out of the TCU is a mystery but not as much as those fans.

 

It's like a chinese water torture and it's making me crazy. :wacko:

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