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Cooling Fan Does NOT Turn ON!

210K views 30 replies 18 participants last post by  DrivenDaily 
#1 ·
i am working on a 2000 malibu V6. the cooling fans do not turn on and is causing the car to overheat. all relays and fuses have been checked for the fans, as well as checking the fans directly and still getting no response. I had someone tell me that the fans were wired into the a/c system, and that i should try checking out all of the a/c fuses and relays. i wanted to know if this was true or not. and also looking for any suggestions or if anyone has had this problem how did you resolve it??

:confused:
 
#4 ·
you can jumper the relay to force the fan to turn on, supply it with ground, and you can test the fan. this will bypass the pcm, and on the other fan you can just jumper the terminals on the relay block and you should have fan operation, which will verify if your fans are good.

other than that, check your wiring from your pcm to the fan and from the fan to the relay and throughout the circuit, you can test all of this with a digital multimeter and a test light. easy to make a jumper wire, get a fuse holder from autozone or whatever, stick a 10 amp fuse in it or whatever the circuit has, then crimp some terminals on it, relay terminals are the same size as those terminals you get in a pack at the auto stores. just a simple blade terminal will work.
 
#5 · (Edited)
I think you should look at the coolant sensor first, always start at the easiest parts first before you dive head first into a nitemare! That's why service technicians check the obvious first, it's all a process of elimination when diagnosing a problem.

Oh and an EASIER WAY to check out between the PCM and the cooling fans would be to find someone with a laptop and a tuner that can hook into the cars OBD2 port then can run a diagnostic on the whole car. This alone will tell you continuity of the circuits if the PCM is receiving and sending signals.
 
#6 ·
scan tool is only going to tell you so much, diagnosing why the fan isnt working is what we are trying to figure out. you can use a scan tool to figure out if it has a code, and a tech 2 to command the fan on, then if it doesnt work, then you take a test light to the connector for the fan, and if it lights between power and ground, you need a new fan.

sorry, i assumed he didnt have access to a tech 2.
 
#11 ·
Due to Chevrolet's great engineering on their 3.1liter 6V engine, mine is overheating. Bleed the air out first of cooling system and then check if fans come on. If not do not waste anymore time and money!!! This relay saved my engine from overheating!!!

Vehicle: 2000 Chevrolet Malibu

Auxiliary Fan Control Unit
Engine Cooling Fan Controller -- Premium adjustable fan control with push in probe that installs in the radiator fin section. Includes wire harness and A/C over ride relay. Adjustable from 160-210 degrees F. Powers two fans up to 30 amps.

Brand: Hayden Part# 3526-07027018 Price: $29.10 + 7.95 Shipping

http://www.partsgeek.com/catalog/2000/chevrolet/malibu/cooling_system/auxiliary_fan_control_unit.html?brand=hayden
 
#12 ·
Interesting that vivache even found this thread, considering it's nearly 4 years old and was in the Gen7 section. Moved to Gen5&6...

Good info on the relay, too! First post and you're already sharing very useful stuff.
 
#17 ·
If you follow the link in post #11, even though the indicated part number doesn't show up at this time, there are several options that appear to have that all sorted out, and they automatically turn the fans on/off using the temperature.
 
#18 ·
my malibu is a 2001 and the fans no longer turn on high, I've replaced the coolant temp sensor, checked the cnx and they still will not go on high. They will come with the a/c but that's it. So I bought an auxiliary fan control unit but cannot seem to find the wire that tells the fan to come on when the a/c is on. Would you happen to know which color wire from the a/c compressor that I need to tap into? I know that I can by-pass the a/c but I want the fans to also come on wen the a/c is turned on. I checked post 11 but the links will not open for me
thanks
 
#19 ·
Easy way to tell is to turn the engine off, get a test light out, turn the key to RUN but don't start it, then turn on the AC. There are only 2 wires at the AC clutch, one is ground, the other is 12V. Use the 12V wire.
 
#22 ·
Anyone know where this is? I personally dont sorry. Would be good to know...


I would start right at the fan.....work back.....seee a relay? Swap it with a good one...see how ya make out, etc......not sure about how it gets to the pcm
 
#25 ·
i am working on a 2000 malibu V6. the cooling fans do not turn on and is causing the car to overheat. all relays and fuses have been checked for the fans, as well as checking the fans directly and still getting no response. I had someone tell me that the fans were wired into the a/c system, and that i should try checking out all of the a/c fuses and relays. i wanted to know if this was true or not. and also looking for any suggestions or if anyone has had this problem how did you resolve it??

:confused:
I have a 2000 Chevy Malibu ls All of a sudden the fans don't go in to mode with the AC turned on I've done a diagnostic and everything is good including the relays however if I remove the 30 amp ground fuse and the dual mode relay then push Back in the number 2 fan goes into high mode And I install the relay back and both fans come on in high mode I can't figure out why your fans don't come on into high mode when I turn on the AC all fuses and relays are good as well as the trmp sensor. Sometimes the fansceill comenon high mode ones the temp reaches about. 220 Anyone have any ideas
 
#26 ·
#28 ·
@imoldnslow

You can do that, but it'd be better if you had the switch turn on a relay that is under the hood. That way, the switch doesn't carry the current and the risk of overheating the wire and/or switch contacts is reduced. Plus the wire to the relay is smaller and easier to route.
 
#29 ·
@imoldnslow

You can do that, but it'd be better if you had the switch turn on a relay that is under the hood. That way, the switch doesn't carry the current and the risk of overheating the wire and/or switch contacts is reduced. Plus the wire to the relay is smaller and easier to route.
Thank you for the information, I will try to figure out how to route it through a relay.
 
#30 ·
Hello, looking to revive this post if possible - as I am having a very similar set of circumstances. I have a 2006 Chevy Malibu LTZ v6 3.5L. My radiator cooling fans will not automatically kick on.

The fans do work& there is circuit continuity, as they will both kick on if the a/c is turned on. All relays & fuses have been checked for continuity & working condition. The thermostat & coolant temperature sensor have been replaced. The coolant system has been flushed& bled repeatedly. The coolant pump has been stethoscoped for good measure.

Bottom line is: the radiator fans are not kicking on, even when the temperature meets or exceeds operating temperature/mid-line on the temperature gauge. I've had it to a mechanic twice who claims there are no codes& has costed me hundreds to no avail.

Any help would be profoundly appreciated!
 
#31 ·
Hello, looking to revive this post if possible - as I am having a very similar set of circumstances. I have a 2006 Chevy Malibu LTZ v6 3.5L. My radiator cooling fans will not automatically kick on.

The fans do work& there is circuit continuity, as they will both kick on if the a/c is turned on. All relays & fuses have been checked for continuity & working condition. The thermostat & coolant temperature sensor have been replaced. The coolant system has been flushed& bled repeatedly. The coolant pump has been stethoscoped for good measure.

Bottom line is: the radiator fans are not kicking on, even when the temperature meets or exceeds operating temperature/mid-line on the temperature gauge. I've had it to a mechanic twice who claims there are no codes& has costed me hundreds to no avail.

Any help would be profoundly appreciated!
Check the other thread where you posted this same issue. I responded there.
 
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