msmithmmx Posted August 17, 2007 Share Posted August 17, 2007 I had a very long post going before but I have decided to start over and summarize it. HELP ME The Car: I have a 97 Legacy 2.5 180K miles that is overheating when I bought it. It did have a check engine light for a speed sensor The Problem: The radiator fans will not come on. They will not turn on when the engine is at temp and it will not turn on when the AC is turned on How to force them on: I do one at a time 1) Disconnect the middle bulk head harness. This throws 3 codes a) P0117Coolant Temp Sensor P0122 TPS c) P0325 knock sensor 2) Disconnect the Coolant Temp Sensor 3) Connect the green diagnostic connecters under the dash driver side 4) Ground out the fan at the ECU What I have replaced 1) Coolant Temp Sensor 2) ECU 3) Every Relay in the engine compartment fuse box 4) Speed sensor 5) I checked every fuse in the car What I am convinced of: 1) I have a Short in the engine wire harness 2) Something is wrong with AC system Notes: I have 8 volts at the wire that connect the engine coolant temp sensor when I disconnect it from the coolant temp sensor Quote Link to comment Share on other sites More sharing options...
Manarius Posted August 17, 2007 Share Posted August 17, 2007 Can you plug in a reader to check what temperature the ECU sees the water being? Quote Link to comment Share on other sites More sharing options...
Cougar Posted August 17, 2007 Share Posted August 17, 2007 First let me say that since you already have a lengthy thread going on for this problem you shouldn't start another one for the same thing. This leads to needless running around on things already covered though you did state a lot of the things we previously covered. You could have just summarized in the last thread. In the previous thread I wanted you to measure the voltage of the 2-wire coolant temp sensor for the ECU. It looks like you got 8 volts across the wires. I'm not sure what the voltage should be but that may be low and if so that means there is a problem on those wires somewhere. I would think there should have been a code set if that was the case so maybe this is really okay. Manarius's idea of looking at the coolent temp through the ECU is a good one and would verify the circuit if the display shows normal temps. Quote Link to comment Share on other sites More sharing options...
msmithmmx Posted August 17, 2007 Author Share Posted August 17, 2007 Ok, how do I verify it at the ECU, all I have is a OBDII reader and a multi-meter from radio shack. Quote Link to comment Share on other sites More sharing options...
porcupine73 Posted August 17, 2007 Share Posted August 17, 2007 If you can somehow get your hands on a scangauge, it will tell you what the ECU is reading as the engine coolant temp. Quote Link to comment Share on other sites More sharing options...
msmithmmx Posted August 18, 2007 Author Share Posted August 18, 2007 OK OK, Fixed. I installed a Used OEM Coolant Temp Sensor and now the fan roars on when its at temp. Turning on the AC does not engage the fan nor does the clutch come on. I am calling this a seperate issue. I hate lending my tools out because I do not have my ac test guages. Thanks to all that have helped me. Quote Link to comment Share on other sites More sharing options...
Cougar Posted August 19, 2007 Share Posted August 19, 2007 Good deal. One down and one to go. The AC fan is still going to need some investigation. You're welcome for the help. Thanks for the feedback. Quote Link to comment Share on other sites More sharing options...
OB99W Posted August 20, 2007 Share Posted August 20, 2007 [...]Turning on the AC does not engage the fan nor does the clutch come on.[...]Might be due to insufficient refrigerant charge. See this thread for a way to check for that without gauges: http://www.ultimatesubaru.org/forum/showthread.php?t=59414 Quote Link to comment Share on other sites More sharing options...
msmithmmx Posted August 20, 2007 Author Share Posted August 20, 2007 I tested with the gauges. There is 0 charge in the system. And that explains why the clutch will not come on Quote Link to comment Share on other sites More sharing options...
lmdew Posted August 20, 2007 Share Posted August 20, 2007 I had a slow leak on my 98 Impreza OBS. I replaced all the orings, but the only ones that looked bad were the two on the compressor. It fixed the problem. The compressor orings had taken a set and were flat on one side. PS take the orings with you to match them. Even the Subaru Dealer could not pull up the correct part number and wanted to order the parts shown as none were in stock. Quote Link to comment Share on other sites More sharing options...
Cougar Posted August 20, 2007 Share Posted August 20, 2007 I tested with the gauges. There is 0 charge in the system. And that explains why the clutch will not come on Well you are closing in on the trouble. Quote Link to comment Share on other sites More sharing options...
OB99W Posted August 21, 2007 Share Posted August 21, 2007 I tested with the gauges. There is 0 charge in the system. And that explains why the clutch will not come onThere's also no reason for the radiator secondary cooling fan to come on when the A/C switch is "turned on" if the compressor can't run. Quote Link to comment Share on other sites More sharing options...
msmithmmx Posted August 21, 2007 Author Share Posted August 21, 2007 What you have all helped me with to date 1) Replaced Bad AC/Heater resistor. Now all speeds work for the interior fan 2) Busted Coolant Temp Sensor. THIS MUST BE REPLACED OEM 3) AC Clutch not turning on, I will do a leak test this weekend. What would all of this have cost at the dealer? Quote Link to comment Share on other sites More sharing options...
Cougar Posted August 21, 2007 Share Posted August 21, 2007 It's hard to say for sure but I would think a good savy tech could pin down the troubles within a couple of hours. Fixing the troubles may take longer. Quote Link to comment Share on other sites More sharing options...
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