radiator fan runs way to much

[dlnelsonroca]

Hello! My truck has been running the double electric fans quite a bit for some time. I had a high fan relay go bad yesterday, which I just replaced. The fans now run about 70% of the time once the engine is up to normal operating temperature. The coolant temperature sensor I assume is be working fine, since it registers at 210 as seen on the dash. Is there a another sensor of some kind to regulate when the fans switch on? If so then where, please so I can replace it. Or any other experienced advise would be appreciated. Thanks!

 

[dlnelsonroca]

Plus I'm not sure of the correct relays for the fan cooling in the under the hood fuse box. The have different numbers, it seems. Or are they all three the same, R1, R2, and R4?

 

[Mooseman]

It would help if you would tell us what year/model/engine you have. From you profile, I got:

Year 2013
Make Chevrolet
Mode l Silverado
Trim LT
Engine 5.3L V8
Drivetrain 4X4

Then I would hear over to https://charm.li/ and look up the wiring diagrams for the fans, which should tell you the location and number of the relays. You can also look up the owners manual which should give a full description of each fuse and relay in the fuse box. If you don't have the original printed manual, it's available here:

Chevrolet Manuals and guides​

 

[mrrsm]

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[Mooseman]

The AI might be wrong . If this is a discreet type fan relay system, which I assume by the year, it does in fact have a third relay. There would be fan1 and fan2 with the third relay as the bridge between the two that will run them either in series (both 50%) or parallel (both 100%). It's the PCM that controls all fan relays using the single temperature sensor. If your fans are running at 50%, I would assume that all three relays are good as that requires all of them to work. However, if you mean to say that the fans run at full speed 70% of the time, I would suspect that the third relay is not operating and just letting them run at 100% each time the PCM commands for half speed as that is the default of that relay.

Another thing that the AI forgot to mention is that the fans would also run if the A/C is running, and that includes having the HVAC set to any defrost setting, which automatically turns on the A/C system. And IIRC, if the transmission temperature is too high, this also triggers the fans.

 

[dlnelsonroca]

Thanks for the replies! The truck on my profiles is correct. Sorry for not writing it in the post. I will check about the fans, if they are both running both at the same time every time, then change out the relays if necessary. Are the three relays all the same ones? I haven't been able to confirm that anywhere I've looked. I will probably change the coolant sensor just in case that's been an issue all along. I downloaded the owners manual and the wiring diagrams, which helped clarify things for me. Many thanks to all! I'm an hour from a decent auto parts store, hoping that they'll have the parts here in somewhat rural Mexico. I'll write back with the results within a few days!

 

[Mooseman]

IIRC, they are not all the same. Two are just 4 pins (SPST), the other one, the in between one, is 5 pins (SPDT). However, they could have used a SPDT type for all of them and use two of them as SPST. You will have to check them physically to correctly identify them.

 

[dlnelsonroca]

Hello again. Great advice, and many thanks. I was able to find all the parts I needed, and the problems seems to be fixed. replacing the relays did the trick for the fan issues, I also replaced the coolant temperature sensor and the thermostat for good measure. Yesterday the truck ran great, and the fans came on only when they were supposed to. While changing the thermostat I notices that one of the belts was splitting, and so changed that too. That would probably have been an problem on the side of the road somewhere!