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Cooling Fans Not Working

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33K views 5 replies 4 participants last post by  Maven76  
#1 ·
Okay, so a preface to this: I hit a deer on Halloween and banged up the front end. The fans needed to be replaced and fell apart as soon as I removed them from the engine.

I did replace the fans with similar ones from an Impala in the junkyard, plugged both fans in and bolted them onto the radiator, so everything appears to be hooked up right.

But I tested it the other day and even though it's relatively cold and the thermostat is stuck open, the coolant temp just slowly creeps up, even going past 200-215 without the fans turning on.

Not sure if it could be the fuses (maybe they shorted out during my accident?) or the fan I scavenged was bad (not sure how to tell, it looked fine physically) or another third issue I hadn't even counted upon.
 
#2 ·
I wonder if your relays are going bad? (Read edit first)

In your lower underhood fuse block on the passenger side, there are three relays that control your fans. They go #3 , #2 , #1 (L to R I believe). #1 controls the primary cooling fan (driver's side), #2 is the cooling fan control relay, and #3 is the secondary cooling fan (passenger side).

I would check those maybe, if you're sure the fan should be on. You could check the terminals with a test light to see if there is current, or jump them with a wire to see if that helps your situation and maybe help determine if your problem is relay related.

In the same fuse block are also the fuses for the cooling fan. I would check those as well, maybe something just shorted while you were installing the new fans. There should be three fuses as well, labelled Cooling Fans, Fan Cont #2 & #3 , Fan Cont #1 .

Edit: Actually, I would check the fuses first, then the relays. If they're all okay, it might be a bad ground (they can do straaaange things) or a bad fan. I do not know how the fans are triggered, whether it's BCM, ECU or a thermostat-driven switch, but if you could find out, those are potential avenues to explore as well.

Hope this helps.
 
#3 ·
You have a 3.4L right?
Stock fan turn on temp is low at 220 and high fan is around 225-230. Since the motor is all aluminum, unlike the 3.8, they can get away with it.
 
#6 ·
I think its been covered, but yeah check your fuses. if the fans were on when you hit the deer you couldve blown a fuse.(though not likely)

heres the excerpt from the service manual regarding fan operation.

The BCM will request low speed cooling fan operation from the PCM under the following conditions:

•Engine coolant temperature exceeds approximately 103°C (217°F).
•When A/C is requested and the ambient temperature is more than 10°C (50°F).
•A/C refrigerant pressure exceeds 1310 kPa (190 psi).
•After the vehicle is shut off if the engine coolant temperature at key-off is more than 117°C (243°F) and system voltage is more than 12 volts. The fans will stay on for approximately 3 minutes.
The BCM will request high speed cooling fan operation from the PCM under the following conditions:

•Engine coolant temperature reaches 110°C (230°F).
•A/C refrigerant pressure exceeds 1655 kPa (240 psi).
•When certain DTCs set.