Cooling Fan not coming on

Post by **subzerocarfanatic** » 17 Nov 2019, 17:05

I noticed after taking the car for a test drive the coolant fan is not coming on and the temp gauge was right at the halfway mark almost.Before i done all the work on it that it would come on even if i only started and ran the car for 1 minute and the fan would stay on for a minute or 2, now i can run it 10 minutes straight and no radiator fan response, any ideas, i double checked my plugs and wiring.
One other thing i forgot to mention, the low coolant light is staying on as well now and coolant is full.

Post by **FlyingVolvo** » 17 Nov 2019, 18:12

The fan only runs when the coolant temperature justifies it. I don't remember the exact value that triggers it. Most normal day-to-day driving with decent airflow won't make the fan come on. The fan will always turn on with the AC though, so you can try that to see if it works at all.

As far as the coolant level light, you likely just need to replace the level sensor at the bottom of the reservoir. Or you could just jiggle the float inside the tank and see if maybe it's simply stuck.

Post by **subzerocarfanatic** » 17 Nov 2019, 20:30

Ok, thanks for the input, i will try that.

Post by **subzerocarfanatic** » 18 Nov 2019, 14:34

I turned on the AC and the cooling fan is still not engaging. It ran before all the work was done, more than it should have probably, considering that even if i started the car then turned it right back off the fan would come on soon as the car was turned off.Now no fan at all, go figure, lol

Post by **RickHaleParker** » 18 Nov 2019, 15:07

1. Disconnect the Engine coolant temperature (ECT) sensor.
2. Place a 150 -170 Ω resistor across the wiring harness.
3. Start engine see if the fan is running.

184 Ω = 100 °C (212°F).
170 - 150 Ω corresponds with a temperatures greater then 100 °C (212°F) .

Post by **subzerocarfanatic** » 18 Nov 2019, 15:15

This is why i love this site, you guys are Very Volvo fluent! very knowledgeable! where can i get a 150 ohm resistor at sir.....

Post by **abscate** » 21 Nov 2019, 18:19

Red Red black if I remember by Horowitz and Hill

Sadface - we used to go to Radio Shack, now all stores are Taco Bell Amazon

Probably cost about a nickel, with $5.99 for shipping

..One of my favorite Geek Cartoons

Post by **subzerocarfanatic** » 21 Nov 2019, 18:45

Yeah, we no longer have a radio shack here, even though they were pricey you could almost always find the parts to fix most anything, is there any way to dip it in really hot water to try to make it come on so i know if it's bad, it worked before so i'm kinda puzzled.

Post by **subzerocarfanatic** » 25 Nov 2019, 12:24

Well.... i have my cooling fan back working, not sure exactly what it was i pulled apart the coolant temp sensor plug and cleaned it with CRC Electric cleaner and double checked fan relay plug at radiator area and when i started it yesterday the fan is working normal, or it's working i will put it that way, to me it doesn't seem normal for it to kick on after only running the car for 2 minutes, not even long enough for Tstat to open up, but soon as i started it the cooling fan came on and stayed on after i turned engine off it stayed on for at est 1 or 2 minutes. Way it did when i bought it.

Post by **ZionXIX** » 25 Nov 2019, 16:47

It probably thinks the temps are too high when they are not.