air conditioner

[JungloSonic]

yesterday, I let the engine heat up to 113 degrees Celcius. The fan is suppose to run at low speed at 99 degrees and at high speed at 109 so the fan should have gone on at some speed but neither low or high speed came on. The only time the fan goes on is when a/c is on. I have bought an OBD scanner that shows that on board computer is receiving temp (started at 23 degrees and gradually went up to 113 as engine was running)
The fan assembly has a relay with resistor (similar to attachment)that is involved in slower speed ..Could this relay be the problem? Most of the green covering is flaking off and there is some rusting.

 

[JungloSonic]

I got a "call" at the relay in the engine compartment (tested with multimeter) and the relay is good. However, when I checked the 3 wire connector (connects to resistor relay) of the fan there was no power there? When I turn the A/c on there is 14V power there ?

 

[ozonetrooper]

Correct, I believe the fans only run when the a/c is on.

 

[JungloSonic]

well, new fan received. The relay at fuse box is receiving call to turn on the fan. When I jump the relay, the fan goes on. The relay was checked in another slot and works, Yet when the relay is in the slot the fan doesn't go on?? Wiring must be good if I can jump the relay and fan works..I am stumped!!

 

[JungloSonic]

I placed a jump on temp sensor connector at the bottom of radiator and the fan didn't go on so likely that is not the problem.
Where is the other temp sensor. I see what looks like 2 sensors. One on thermostat housing and another next to it on engine block..Which of the 2 is the engine coolant temp sensor?

 

[ozonetrooper]

Where is the cooling fan sensor located?

The ECT sensor is typically near the thermostat in the cylinder head or thermostat housing.

Chevrolet Sonic Repair Manual: Engine Coolant Temperature Sensor Replacement (Water Outlet) - Engine Control Sensors - Engine Control - Internal Combustion Powertrain Control - Powertrain

www.csmans.com

 

[JungloSonic]

I have ODB2 attached and seems to read ECT ok. 24 degrees celcius and goes up gradually to 110 so I might assume it is fine for now.

 

[fnkie]

same problem! the ac works sometimes. it all makes sense no, it happened a few years ago, at the same time the fan bearing went out and ruined the radiator. so I replaced and problem went away. but this time everything works... still only works sometimes.