sahlomonic

iTrader: (1)

Tried searching here and on Google last couple days but have yet to find help specific to my concern.

After I first start the car in the morning, the pass side fan will kick on after a couple minutes, and stays on until the engine temp cools down to ambient temp long after the car has been shut off. When the car shuts off, the fan also shuts off.

I'm confused on what to check. From previous searches I would guess the fan switch, and that's located on the pass side of the block, correct? The relay(s) on the firewall drivers side have been checked and are good, but not sure if that would cause the issue.

jharrison5

The system is all controlled by the ECM. It should kick on at 238*F and off at 214*F or when the A/C is activated. Both fans should have a corresponding switch and relay.

I would start with the switches. Turn the ignition to run and unplug the coolant fan switch connector, if the fan turns off the switch is bad.

If it stays on remove the FP fan fuse and check the dark green/white (or what ever color your's happen to be) wires for shorts to ground. If you pull the fuse and the fan doesn't turn off then the relay is bad.

If none of that checks out then there might be a problem between the fan switches and the ECM.

henryd3

iTrader: (128)

Have you changed the coolant lately? Once when I had a guy change my fan switch he had his young apprentice do it and somehow created an air bubble in the head . Fan was doing the same thing, which was responding to the temp of the head itself and not the coolant. Took forever for the fan to go off. Took out the thermostat and it was dry underneath. Filled properly and problem went away. Long shot, but maybe worth checking??

sahlomonic

iTrader: (1)

That's an idea I haven't thought of yet. Oddly enough, the pass fan hasn't kicked on at all today, which is a first since purchasing the car over 3 years ago. I did change the coolant best I could last summer, and I suppose it's possible there was an air bubble trapped. I topped coolant off last weekend (maybe added half a gallon). I am still waiting to finish fixing my truck first then I'll park the Camaro in there and look at the fan switch.

brett89

Curious if their was an update to this? I seem to have the same problem.. start my car from cold and both fans will be off .. after a couple mins later the secondary fan will come on then within 30secs the primary fan will come on .. Looking at my auto xray scanner the coolant temp is reading 111'F.. shut the car off both fans will go off.. turn key to on with engine off and the secondary fan clicks on and primary fan will be off. let it cool down to ambient temp and check it again with key on and engine off the fan will be off. Any input would be great

Ron U.S.M.C.

I always thought one of the two fans was controlled by the switch in the head and the other by the ECM.

That would enplane why one of the fans is acting strange.
Its a "bad" switch in the head. Its controlled by the engine temperature and grounds out in order to engage the fan.

All you would have to do is un-hook the wire on the switch and see if it stops the fan.

If that's it,it would be a perfect time to install a switch that comes on at an lower temperature and install a lower temp thermostat to lower your running temperatures if you want.

aseychell

It is exactly as Ron is explaining. I know for sure because I have lately rewired the whole system.

brett89

Would that also explain why my primary fan comes on right after even though it's not up to temp? Does the ecm some how see the secondary fan on and right away click on the primary?

aseychell

To clarify. Primary fan is the one controlled by a heat triggered switch on the passenger side head. This is normally triggered at a lower temperature than the secondary fan which is controlled by the ECU reading temperature from the driver side head. The secondary fan is also triggered when the AC is on.

Both fans are independent of eachother and the only feedback in common between them is the actual temperature of the coolant in the engine. If the engine is not properly filled with coolant such as having air locks, temperature readouts will not be consistent and fans may be triggered erroneously.

henryd3

iTrader: (128)

Actually, you will come to find that the primary(driver side) fan is controlled by the ECM using information it gets from the CTS sensor generally near the thermostat housing. The driver side head sender is for the temp gauge on the dash, and the secondary fan switch is in the passenger side head. These two systems work completely independent of each other . AC on also actuates the secondary fan(passenger side) by grounding out it's relay just as the fan switch does.

brett89

If their independent then why do they both come on at 111'F ? Well before the car warms up.... when I bought the car 3 years ago I had Brian (tuned performance ) burn me a chip and one of the things he did was have my fans come on at 200 and off at 185.. I always thought the fans came on to soon .. wasn't till this week I investigated at what temp they come on .. I originally thought maybe Brian made a mistake with the input in the chip .. so I put back my stock one and still the same thing

henryd3

iTrader: (128)

Maybe somebody "customized" the relays together so they come on sooner??You would need to look for any non stock wiring that is lurking around. is this a thing that just started, or has it always done this?
If the computer it turning the fans on too soon then maybe the CTS is giving the wrong info to the computer?

brett89

I believe I have found my problem.. a sticking temp switch!

Question: I have my primary fan programmed to come on at 200 and off at 185 .. What's a good temp to have my secondary fan to come on ? I'm thinking a switch for a tta on at 204 and off at 188 I believe.. looking at options?

Ibazzabar92

mine did that but it was the wire to the secondary fan that got melted onto the exhaust manifold. So basically the wire was grounded all the time and thats how the fan comes on anyway. lol