Radiator cooling fans not working

[Lanster]

Hi can anyone suggest what I should check to find the problem ,the rad cooling fans are not engaging , also what temp do they engage at.I see there is three separate relays. Any direction or help,is apreciated. If I did not mention it this is a c5
Thanks

 

[Rruuff Day]

Typically the coolant has to reach a pretty high temperature on most vehicles before the electric fans engage. One relay should control low speed which comes on initially. Then when the temp reaches another plateau, i believe another relay kicks them into high speed. Then when the temp drops to a certain level, the third relay shuts them down. This is experience not from a Corvette unfortunately so don't take that to the bank. but I would expect it to be similar in operation.

 

[CableGuy]

The fans will engage at low speed when the coolant temp reaches 226 (108c) degrees. If the temp keeps climbing, the fans will change to high speed at 235 (113c) degrees. This assumes that the vehicle has a stock tune and the fan turn on temps haven't been adjusted. All cooling system fans will be disabled once the vehicle exceeds 35MPH (56Km/h). Once the vehicle slows below the threshold, the fans will resume operation. The fans will also be engaged when the A/C is turned on (assuming that you are under the 35MPH threshold).

 

[corn4th]

Thank you guys. Valuable information. I have watched the temperature rising but have never or very seldom heard the fans kick in. So high temp. Readings are the normal in slow traffic.

 

[kacey62]

I too was spooked by what I thought were very high temps before fan engaged.in my 03. I found if I turned on the A/C the low speed fan engaged and temp dropped dramatically. These engines are designed to run way hotter than than us "old Guys" are used to seeing.
Always did this in city driving if stopped or slowed in traffic. They actually make a "parade switch" to manually turn the fans on!

 

[Riley P]

Man, the first time I saw my car going over 200 degrees, I was getting nervous, then 210....220... I think the highest I ever saw was 228, so right after the fans turned on. As stated, definitely not the norm for someone who had older V8's and liked seeing the temp around 180. Since then I've had the fans reprogramed to come on low at.....not actually sure... I think 190? Or where ever the thermostat is set for, and high at 15 degrees after that. I still have to blow out my radiators from the back. Apparently that helps a TON on our cars as they such up a lot of debris from the road.

 

[Lanster]

Thanks again for the info , I will check and clean out the rads, there probably dirty. That parade switch sounds like an idea as well