If your Chevy Impala’s cooling fans are not working, it may be due to a fuse or relay issue, or a bad fan. Check the fuses and relays, and refer to the service manual to troubleshoot the problem. Let’s discuss in detail.
1. Chevy Impala 7th Gen’s cooling fans are not working
Your Chevy Impala 7th Gen’s cooling fans are not working properly even though you replaced them with similar ones from a junkyard. The coolant temperature rises above 200-215 degrees, and the fans do not turn on.
You suspect it could be a fuse issue, a bad fan, or some other third issue.
To fix the issue, you should check the fuses and relays first. In the lower underhood fuse block on the passenger side, there are three relays that control your fans.
#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).
Check those relays, and if you’re sure the fan should be on, test 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.
Next, check the fuses for the cooling fan in the same fuse block. There should be three fuses labelled Cooling Fans, Fan Cont #2 & #3 , Fan Cont #1.
If all fuses and relays are okay, check for a bad ground or a bad fan. You can determine if the problem is with the fan by finding out how the fans are triggered, whether it’s BCM, ECU, or a thermostat-driven switch.
If you have a 3.4L engine, note that the stock fan turn-on temperature is low at 220, and high fan is around 225-230.
Check the excerpt from the service manual regarding fan operation to understand how the BCM will request low speed and high speed cooling fan operation from the PCM under various conditions, including engine coolant temperature, A/C request, and refrigerant pressure.
Additionally, if the fans were on when you hit the deer, you could have blown a fuse. While it’s not likely, it’s still worth checking the fuses as a precaution.
When the AC is on, the fans are on almost all the time based on the head pressure of the compressor, so that automatically keeps the engine temperature cooler.
2. Cooling Fan Not Turning On (2010 Chevy Impala)
Your 2010 Chevy Impala’s secondary cooling fan is not turning on, which causes slight overheating on long trips. You changed the three relays for the fans, but the problem persists.
You suspect that the passenger side fan is not turning on despite reaching appropriate temperatures, and you’re not sure where to start diagnosing the problem.
Check the wiring for any chafing and weather pack connector if it’s fully seated, and see if the connectors are corroded. Ensure that both radiator cooling fans should run with the AC or defroster turned on.
If you find no issues with the wiring, replace the weather pack connector.
Since you ran the connection from the driver’s side radiator fan to the passenger side, the AC fan runs constantly and at high speed, keeping a decent temperature to run the car without overheating.
The driver’s side fan seems to run intermittently once it reaches the optimal temperature. However, it’s still a temporary fix.
To figure out what’s causing the lack of current to the left radiator fan, start diagnosing the problem with the fuse box. Check the fuses, and if they’re okay, it might be a wiring issue that you need to trace back. You may need a mechanic’s assistance to identify and fix the issue.
3. Cooling Fan Issue: Troubleshooting Overheating on 1996 Chevy Impala
You are experiencing overheating with your 1996 Chevy Impala since only the secondary passenger-side cooling fan works, and you cannot find the problem even after checking the relays, fuses, and sensors.
Check the coil of the relay, which may not be energized due to a defective coolant temperature sensor, which can cause the driver-side fan to remain off.
Keep in mind that the fan on the driver’s side will not come on until the fan on the passenger’s side cannot keep the temperatures under control.
Additionally, it’s typical for the car to run around 15* F higher than the t-stat opening temperature, and the gauge on the dash may not be entirely trustworthy. Lastly, bleeding the cooling system at the thermostat housing may also be a cause of overheating issues.
4. How to troubleshoot cooling fan issues on a Chevy Impala 8th Gen
You are having issues with the cooling fans on your Chevy Impala 8th Gen as they are not turning on even when the engine temperature rises above a certain level.
You have checked the fan relays and fuses but cannot find the root cause of the problem.
The power to the fan relays on the Chevy Impala 8th Gen comes from the 30 amp fuses.
However, the PCM supplies a ground to turn the relays on when the engine reaches a certain temperature, which in turn, turns the fans on.
To check if the fans are turned on by the PCM supplying a ground, check if you have power at the relays at all times.
Both coil-side terminals of all three relays must be hot until the fan starts. On the relay for Fan1, both pins 86 and 30 should show 12V+ or light up red if tested with a test light.
On the relay for Fan3, both pins 85 and 87 should also show 12V+ or light up when tested. If you test for continuity between Fan 3 Relay Pin 87 and the bottom pin of the Fan2 fuse or between Fan 1 Relay Pin 30 and the top of Fan1 Fuse, it should show a connection.
To check if the engine temperature sensor could be causing the issue, test for 5V to the sensor and ground on the other side. If it’s a 2-prong sensor, ground for one and 5V for the other.
The sensor should test out around 2 or 3k Ohms cold and when the car heats up, it lowers the reading. This changes the information from the 5V because it is going to the computer and it reads the difference.
If you still cannot find the root cause of the issue, try grounding the ground side of the relay coil directly to the chassis or through a switch for each relay, like SW 1 turns both fans on low speed, and SW2 on high speed.
However, be careful not to do anything that would make the issue worse, and do not mess with ECM control side of these relays unless you are sure it is safe to do so.
In conclusion, if you are experiencing cooling fan issues with your Chevy Impala, it’s essential to start by checking the fuses and relays, as well as the wiring and connectors. Additionally, it may be worth consulting the service manual and seeking professional assistance if you cannot identify the root cause of the problem. Remember to be cautious and avoid making the problem worse while troubleshooting.