Engine cooling fans not working - Page 2

dbailey · 05-29-2007, 06:03 PM

Found all of the fuses and they're good. How do you determine if a relay is bad. I don't think its that because the fans come on when the A/C is turned on but I don't think they're coming on when the A/C is off. The thermostat is not that old. I'm getting a leak right around that little hose area that connects to the radiator coming from the coolant tank. The hose is new and I've cranked the new screw type clamps down about as tight as I can. The heat guage moves up a bit above half way when I'm sitting and then seems to be OK when driving along. Its never had a problem in the past though when sitting still.

strtrydr · 05-30-2007, 05:35 AM

to check the relays you would need to have a Multimeter and then Ohm check the tangs on the relay (one alligator clip to one tang & the other alligator clip to the other tang.) Check to see if the number on the display is within the limits (should be listed on the relay ... somewhere.) If not you have a bad relay. If the display doesn't even show a number then you have some broken internals in the relay ... so yea that would be bad too.

dbailey · 05-31-2007, 09:06 AM

Does anybody know if the colling fans are circuited differently for when the a/c is on and when it is not. I mean, would there be a circuit that recognizes to turn them on when the a/c is turned on and a separate circuit that senses the temp of the engine and turns them on?

Cliff8928 · 05-31-2007, 12:42 PM

The cooling fans are controlled by the PCM. There could be two circuits depending on if they have more than one speed to them.

dbailey · 05-31-2007, 01:30 PM

Hmmmm.....wonder if the computer is slowing dying? I recall last year when I took a road trip from North Carolina to Florida when I came off of the freeway to get gas it wouldn't start or stay running. Died as soon as I pulled away from the pumps. Put it in neutral and it started. Started to get back on freeway and it died. Back to neutral and started. This time I turned the cruise off and it hasn't happened again. Just always wondered if by leaving the cruise on all the time if that had been slowing frying the circuit in the computer. And now maybe this is just another symptom of the computer going bad. I recently let it sit in the driveway and run until I hoped it would get hot enough for the fans to come on and they didn't but I was seeing some steam start coming from that area around where the little hose from the coolant tank connects to the radiator. Was wondering is it was trying to overheat since the fans weren't coming on? Gotta find my multi-meter to check the relays.

dtldiaspora · 07-08-2008, 12:09 AM

anyone ever figure this out? i'm having this issue now fans won't come on unless i turn the a/c on...

01silveralero · 07-08-2008, 05:09 AM

^i had to replace the fusebox to solve my problem.i believe mine used to only come on when a/c was on i didnt remember exactly though.

lonnie · 07-08-2008, 07:29 AM

You could just run a switch to them and turn them on when you want.

...I've noticed that when I'm at a light or stopped with the car running she runs hotter but as soon as I'm on the go she cools right down to the half way mark. I guess that is to be expected though.

dbailey · 07-08-2008, 07:41 AM

I noticed the other day that my fans came on without the a/c needing to be turned on.

They may be set to only come on when it gets really hot. My temp guage was at like 3/4 the way to the top when they came on. Was climbing some pretty steep hills in the mountains of Western North Carolina. When I stopped and went inside a store, that is when it got so hot. Cooling fans cooled it right down though. Is your temp guage getting all the way to 3/4 and fans still not coming on?

Cliff8928 · 07-08-2008, 12:31 PM

Yeah, I think 3/4 is the normal temp for them to come on.

01silveralero · 07-08-2008, 01:27 PM

^incorrect it should be a little above half line when they come on. which is 230 degrees. middle line is 220. 120 is bottom. 170 is 1/4 line. 270 is 3/4 line. top im not sure the temperature but that is head gasket blowing and possible engine failure stage.

dtldiaspora · 07-08-2008, 05:26 PM

ya mine only come on if i turn the a/c on, if i don't run my a/c all the time i will over heat

Cliff8928 · 07-09-2008, 03:01 AM

Quote:

Originally Posted by 01silveralero

^incorrect it should be a little above half line when they come on. which is 230 degrees. middle line is 220. 120 is bottom. 170 is 1/4 line. 270 is 3/4 line. top im not sure the temperature but that is head gasket blowing and possible engine failure stage.

I don't remember seeing degrees on my temperature gauge.

However on my '04 Ecotec, the fan stage 1 comes on at 223°F and stage 2 at 230°F

01silveralero · 07-09-2008, 04:44 AM

Quote:

Originally Posted by Cliff8928

I don't remember seeing degrees on my temperature gauge.

However on my '04 Ecotec, the fan stage 1 comes on at 223°F and stage 2 at 230°F

i had watched it many times with my friend's "superduper" scantool.

it shows literally eventually u can think of. rpm, timing, coolant temp (even when it rises or goes down), o2 readings, and so on. it was like 1000 dollars for it or somewhere around there.

dtldiaspora · 07-09-2008, 05:25 PM

so basically no one knows why the fans do this?

Cliff8928 · 07-10-2008, 02:16 AM

It's impossible to tell without proper diagnosis and a scan tool.