Well i have had my 95 mustang gt for about 3 weeks now. Today i go to shut it off and i can still hear something... the fan is staying on. What would cause it?? I pulled the high current fuse under the hood to keep it from draining my battery. The fuse is fine and i even tried a different one to make sure but it keeps running. It didnt get hot or anything. I will try to go pull codes as maybe it will help. Is there a fan relay and if so where is it? it isnt in the box under the hood i checked that already so i assume there isnt one just the high current fuse. Anyone know what could be wrong?? I guess it could be worse the fan could not work and then overheat. I am taking it to the mechanic tomorrow to get the ac fixed so i guess if all else fails see what he says.
Fan stays on constantly
- Thread starter Josh79
- Start date
Methodical
15 Year Member
If the fan stays on, the fault could be the Constant Control Relay Module (CCRM), which is a little black box attached to the coolant overflow tank - it houses the fan relay - or the engine coolant temperature (ECT) sensor , which is located just to the left and behind the thermostat housing. You can check the ECT when it is cold (50-65 degrees F = 58,700-40,500 ohms. Start the engine and get it to normal operating temperatures and the reading should be 3,600-1,840 ohms.
Life with a Mustang would be little simpler if you get the Haynes Automive Repair Manual - its only about $12-$15. With it you will began to tinker with your car with a little more courage.
PS: Also do a search on here you probably will find an exact answer. But sometimes you have to Methodically diagnost things in order to eliminate possibilities. GET THE BOOK
Peace
Life with a Mustang would be little simpler if you get the Haynes Automive Repair Manual - its only about $12-$15. With it you will began to tinker with your car with a little more courage.
PS: Also do a search on here you probably will find an exact answer. But sometimes you have to Methodically diagnost things in order to eliminate possibilities. GET THE BOOK
Peace
Al's idea is a good one. If the relay latched, the fan could stay on.
Also, take a quick look at your ECT and its wiring. Here's how the low speed fan works:
By default, the computer (passively) and EDF control relay keep the low speed on. This is a safeguard in case the computer has no clue what the Engine temps are (as would be the case if the ECT sensor wiring had an open). When the computer knows the engine temps, it actively turns the fan off. Cool?
Pull up a CCRM diagram and start checking input and outputs for whichever speed is stayin on for you (I assumed low is staying on - it could be high though. If it's high, forget that crap in the paragraph above, as it doesnt apply to high speed).
Good luck.
Also, take a quick look at your ECT and its wiring. Here's how the low speed fan works:
By default, the computer (passively) and EDF control relay keep the low speed on. This is a safeguard in case the computer has no clue what the Engine temps are (as would be the case if the ECT sensor wiring had an open). When the computer knows the engine temps, it actively turns the fan off. Cool?
Pull up a CCRM diagram and start checking input and outputs for whichever speed is stayin on for you (I assumed low is staying on - it could be high though. If it's high, forget that crap in the paragraph above, as it doesnt apply to high speed).
Good luck.
ok ill go check it. i dont have a volt meter (need to get one for other reasons) but ill put a test light on it and see. It stays on with the ign off and i searched and found where someone said they replaced the ign switch and it fixed the fan staying on. Ignition switch is a hell of a lot cheaper than the ccrm
Methodical
15 Year Member
check the 60a fuse on the right under the engine and the 10a fuse. I'm looking at my chilton manual right now. the ccrm pin 3 and 4 are connected to the 60a fuse. pin 1 and 2 are red/orange and are connected to one side of the fan. pin 6 and 7 are org /lt. blue are connected to the other side.
well i pulled the 60a fuse to keep it from running the battery down. I think i fixed it with out having to get any parts. I tried messing with all the wiring and did some stuff. Nothing work so i decided to hook up my code scanner to see if there was a code. I hooked it up and it kicks the fan on normally to test it. Well after it tested it the fan shut off and it hasnt stayed on since. It runs when im driving but shuts off when i turn the key off. I must have a special code reader that also fixes the problem lol. Did my first good burnout to celebrate (had it for only 3 weeks). I need new tires anyways so i might as well use em up
When you hooked up the code reader, did it cycle both fan speeds, or just one? If only one, do you know which one?
You can do further diagnostics with the meter to check the inputs to the relays (in the CCRM) to see if a relay's latching (no input). If there is an input, chances are the relay is doing what it's supposed to and the issue is bad input.
Good luck.
You can do further diagnostics with the meter to check the inputs to the relays (in the CCRM) to see if a relay's latching (no input). If there is an input, chances are the relay is doing what it's supposed to and the issue is bad input.
Good luck.
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