supplybfk Posted September 24, 2009 Share Posted September 24, 2009 The check eng light came on, and I pulled a p0116 (ect sensor circuit) code, reset the light, and it hasn't come back on. So I've tested the fan by giving it direct battery power and it tested good. I backed probed the fan module wires and they were good. The water pump isn't howling. The coolant level was fine, and both hoses were hot so I assumed that the thermostat is opening. The fans, however don't come on. Would it be either the ect switch or the ect sensor a combination of both? Thanks. Link to comment Share on other sites More sharing options...
supplybfk Posted September 24, 2009 Author Share Posted September 24, 2009 OK, according to the Haynes, the ect switch shouldn't have any continuity while cold, but my DMM showed continuity. The ect sensor showed good. Now I am having trouble trying to remove the ect switch. It seems to have two spark plug type wires connecting to the base of the switch. Is this the right switch (the Haynes picture was difficult to compare)? The location description Haynes gave was by the firewall near the coolant transfer side (I'm guessing for the heater core). Thanks. Link to comment Share on other sites More sharing options...
James Matteu Posted September 25, 2009 Share Posted September 25, 2009 When you're looking at your Water Passage, there are two things pointing up (with wires coming out of them) and one pointing sideways (with wires coming out of it). One of the two pointing up looks like the one that is sideways, that is your Engine Coolant Temperature Sensor. The one pointing sideways is the Engine Coolant Temperature Switch. The last of the three is the Engine Coolant Temperature Gauge Sending Unit. It really could be either the Engine Coolant Temperature Switch or the Engine Coolant Temperature Sensor keeping your Radiator Fan from running; not the Engine Coolant Temperature (ECT) Gauge Sending Unit since the ECT Gauge Sending Unit only runs the temperature gauge in the Instrument Cluster. The ECT Sensor is a thermistor that sends information to the Engine Control Module, it's functional range varies logarithmically from 20,000 Ohms at -4 °F (-20 °C) to 100 Ohms at 248 °F (120 °C). The ECT Switch is open (no continuity) below 196 °F. Once closed (continuity), the switch will stay closed until the coolant temperature drops below 5-15 °F. Ultimately, the decision to switch on the Radiator Fan comes from the Fan Control Module sitting behind the Glove Box. How did you test the Radiator Fan? Have you tested the Radiator Fan Relay? Does the car overheat with the fan running constantly*? Is Fuse #8 "Heater Control Relay, A/C Clutch Relay, Cooling Fan Relay, 7.5A" still good? Does the Radiator Fan make any noise while running? * Take a paper clip and stick it into the connector for the Engine Oil Temperature Switch, it's the one on top of the rear Valve Cover. Link to comment Share on other sites More sharing options...
supplybfk Posted September 25, 2009 Author Share Posted September 25, 2009 I tested the fan itself by giving it direct power from the battery using jumper wires. I tested the relay the way Haynes told me by giving power to one lead and ground to another and then tested for continuity . The fuses are fine. However, when I went onto Mitchell, the component locator said the ect switch was on the engine above the transmission I believe, I'll double check. I haven't check the oil temp switch (don't think it's the problem but I'll check). Thanks a LOT for your help. I'll let you know, peace. Link to comment Share on other sites More sharing options...
xxhrdcr4lifexx Posted September 25, 2009 Share Posted September 25, 2009 i may sound like a d!ck on this 1 so dont take it personal. just bkuz the upper and lower hoses get hot doesnt mean your therm is working that could be your whole prob right there, usally in most overheating problems its going to be either your temp switch, thermostat, waterpump, radiator needs to be flushed,and or a bad head gasket. oh and just kuz your pump isnt "howling" doesnt mean it isnt working properly. just a thought on that but most likely not the issue. if it the waterpump itself you may want to change your timing belt while your working on that general area i would flush your radiator with boiling a$$ hot water with a new thermostat, if its not that look into a new temp switch. BUT you said your fans dont turn on, but they work when you tested them. so obviously your motor isnt sending a signal to your fans sayin im hot bi7ch cool me down... so my suggestion on that would be a relay or your temp switch or sensors are bad. just another thought here have you tried running your a/c l8ly kuz normally when you turn the a/c on the fans will turn on.... Link to comment Share on other sites More sharing options...
James Matteu Posted September 25, 2009 Share Posted September 25, 2009 ...However, when I went onto Mitchell, the component locator said the ect switch was on the engine above the transmission I believe, I'll double check... That really doesn't help; here, maybe this will: Engine Coolant Temperature Sending Unit: one Yellow/Green wire. Engine Coolant Temperature Switch: two wires: Green, Black. Engine Coolant Temperature Sensor: two wires: Red/White, Green/Blue. Engine Oil Temperature Switch: two wires: Orange, Black. I want you to stick the jumper wire in the connector for the Radiator Fan Relay on the switch side, I want you to see if there is a good connection between the Radiator Fan Relay and the Radiator Fan Motor. Link to comment Share on other sites More sharing options...
supplybfk Posted September 26, 2009 Author Share Posted September 26, 2009 That really doesn't help; here, maybe this will: Engine Coolant Temperature Sending Unit: one Yellow/Green wire. Engine Coolant Temperature Switch: two wires: Green, Black. Engine Coolant Temperature Sensor: two wires: Red/White, Green/Blue. Engine Oil Temperature Switch: two wires: Orange, Black. I want you to stick the jumper wire in the connector for the Radiator Fan Relay on the switch side, I want you to see if there is a good connection between the Radiator Fan Relay and the Radiator Fan Motor. Ok the relay and connection tested fine as does the oil temp switch. Now the ECT switch location...I am at a dead end as to where it is. Haynes says it's near the coolant passage on the firewall wall side, Mitchell On Demand says it's on the engine above the transmission. With the info you gave me about the green and black wires, I found what appears to be a thermistor switch with green and black wires, but it is T'd odd with the upper hose of the power steering pump. Would that be the switch? If it is, why is it T'd off with that hose? Thanks again. Link to comment Share on other sites More sharing options...
James Matteu Posted September 26, 2009 Share Posted September 26, 2009 Haynes says it's near the coolant passage on the firewall wall side, Mitchell On Demand says it's on the engine above the transmission. The coolant passage is under the throttle body, you are looking in the wrong neck of the woods. On the engine above the transmission doesn't help either. The three Engine Coolant Temperature (ECT) components on a C27A4 are all near the throttle body. Here are some pictures I just took. Link to comment Share on other sites More sharing options...
supplybfk Posted September 28, 2009 Author Share Posted September 28, 2009 Thanks!!! I just changed the switch and reset the check engine light, and everything is good, However, the coolant resevior seems to be emptying out, but I see no sign of leaks. I've filled it up before the fix because I noticed it was low, now the whole resevior was drained after I test drove the car. The coolant never returned, so I filled it again before I left for dinner, and when I came back home, the resevior was empty again. No signs of overheating either. What could be the cause? BTW, thanks for ALL your help. I'm still a green mechanic so I don't have all the experience yet, but you saved me a lot of money. Thanks again. Link to comment Share on other sites More sharing options...
James Matteu Posted September 28, 2009 Share Posted September 28, 2009 Did you bleed your Cooling System while refilling it? It sounds like the Radiator Cap is sucking in coolant. Remember: open the Heater Core by turning the Climate Control Knob to FULL Heat, vent the Cooling System by loosening the Bleed Screw, and leave the Radiator Cap off after filling so that while you idle the car through the first cooling cycle any trapped air missed by the Bleed Screw can still escape. Link to comment Share on other sites More sharing options...
James Matteu Posted October 2, 2009 Share Posted October 2, 2009 Bump, what happened? Link to comment Share on other sites More sharing options...
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