Cooling Fan Runs All The Time

scca vette

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I have aquired a new problem this week. I have been working on the 96 GT and the fan has decided to start running ALL the time, even with the car off. I did a search and did not see any previous threads on this, has anybody ever had this issue? Anybody know what would be causing this?
 

weendoggy

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If this has the CCRM, it is in the fender well behind the splash shield. It has two wires that go into ONE wire that passes through the circuit breaker on the inner fender side (eng. R/Side) then onto the fan itself. If the CB has power all the time, the fan will run no matter what. I'd check that first before diving into the CCRM issue. Pull the CB and if the fan stops, wha lah! Then you need to find out why the CCRM (integrated electronic relay crap) is sending power constantly. Fan is also controlled by engine coolant temp, speed and A/C.

On my '02 the fan has two speeds. Low is normal engine use and when A/C is on, it goes to high (controlled by CCRM). You can check your fan to see if it's running low or high by listening and/or testing the two leads to the fan itself, then determine what side is running all the time with it connected normal.
 

cobrajeff96

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Yea those temp sensors I believe are simple bi-metal strips and they'll surely wear out after a while. So if a multimeter shows continuity between the temp sensor output and ground, the sensor has fully shorted and maybe that could simply be the cause.

They relay inside the CCRM that triggers the fan could be stuck closed in an energized state maybe. Chance it's corrosion on the inside that made it so. Happens.
 

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scca vette

scca vette

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Yea those temp sensors I believe are simple bi-metal strips and they'll surely wear out after a while. So if a multimeter shows continuity between the temp sensor output and ground, the sensor has fully shorted and maybe that could simply be the cause.

They relay inside the CCRM that triggers the fan could be stuck closed in an energized state maybe. Chance it's corrosion on the inside that made it so. HappeIn
Funny you mention the temp sensor. There was a code for temp sensor and we replaced one of the 2 sensors a while back however had been working fine up till now. The question i have is what sensor is what, i never did get a good answer. There is 2 sensors on the front of the crossover (drivers side and passenger side). Do you know what ones controls what?
 

RAU03MACH

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i believe passenger is sender and driver is signal to fan and relay, i could be wrong
 

cobrajeff96

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So if you have a sensor that has a single threaded stud on it where a 90-degree booted terminal hooks on, that's a dead giveaway for the temp gauge. The opposing sensor with the two-wire plastic connector would be the temp sensor for the ECU (often abbreviated as "ECT" in diagrams for Engine Coolant Temp).

A gauge cluster diagram such as attached can often help to discern which is which based on wire color code. There is a chance that the wire colors on the engine bay side of the firewall can change year over year so it's always best to have the diagram specific to the model/year. I have access to detailed diagrams but only when I find myself at the hobby shop I use. Next time I'm there is in a couple weeks give or take. I myself have a 96 Cobra and have already downloaded a lot of diagrams for my own uses, for what it's worth.
 

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scca vette

scca vette

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I was finally able to work on this over the weekend and found the cause of this issue. After removing about everything associated with the cooling fan, I found that there was an Orange wire that was broken in the harness that goes through the passenger fender and to the CCRM. I repaired this wire and all is good again. I will tell you that the fan continued to run with the CCRM and ECU completely removed from the vehicle.
 

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