So I recently bought a 92 accord for $500 as a sort of fixer upper. One of the main problems is that it's overheating. I've replaced the thermostat, both temperature sensors (the one on the front of the engine and the one on the back next to the thermostat housing), the temp switch (the one below the distributor), the temp sensor (also below the distributor). The mechanic before me replaced the radiator and the cooling fan. I bled all the air out of the system the best i could. The only obvious issue i see is that the cooling fan won't come on while the car's running- it only works when the car's off. Another odd thing is when it's overheating, the coolant coming out of the engine is nice and hot, but the coolant going in is cold. So is it the thermostat? But I just replaced it! I can't tell if the coolant's cycling through the engine- could it be the water pump?
Bear in mind I'm still a novice when it comes to mechanics. I'm trying my best lol. I'm very lost.

 

You should do some testing before installing any more parts on the car. When the engine is cold, remove the radiator cap and make sure the radiator is filled to the top with coolant.

Also, start the engine, and turn on the a/c. Do both fans on the radiator turn on?

Does the temperature gauge rise when you are stopped, but drops when you are driving? I'm not sure if your car is drivable.

 

The switches/sensors you installed have different functions.
Temp switch A is on/near the thermostat housing and is a switch that closes at 200 °F. When the coolant reaches 200 when the engine is running, the switch turns on and both fans should turn on.

Temp switch B is on the front of the cylinder head. This closes at 223 °F and will turn on just the radiator fan (larger body fan) when the engine is off to prevent heat-soaking.

The engine coolant temp sensor sends the coolant temperature to the ECU. The ECU uses this to go into closed-loop mode and for the air/fuel ratio. This is the 2-wire sensor under the distributor.

The coolant temperature sender is the 1-wire sensor under the distributor. The only job for the sending unit is to send the coolant temperature to your gauge cluster.


A quick test on the wiring is to unplug temp sensor A, then jump the 2 electrical pins on the connector (not the sensor) together with a piece of wire. See if both fans turn on. Also let us know if the coolant temperature rises or remains normal if both fans run.

 

The car isn't driveable at the moment, the brake lines are rusted. The previous owner told me that it had been overheating while he's driven it. It also overheats at a normal idle too.
Radiator is still full of coolant.
Neither fan turns on when I run the a/c. I jumped the temp switch like you said, and only the radiator fan comes on.

 

Not sure if the temp still rises with the fans on. Gonna need to look into that more.

 

Repeated overheating could have caused a head gasket leak. A quick check is to start the engine cold with the radiator cap removed. See if you have lots of gas bubbles escaping from the coolant and leaving through the top of the radiator. There are some other problems identified from your test that you will need to address, but you might have an underlying head gasket problem to fix at the end.

Jumping temp switch A confirms the wiring is ok between the switch and the radiator fan. It also identifies 2 other problems that you need to address.

1. The condenser fan is not working properly. The quick test is to repeat the same test and hit the back of the condenser fan motor with the handle of a screwdriver to see if this get the fan motor to work. Alternatively, unplug the connector to the non-working fan and use a volt meter to see if you have 12V on the harness side of the fan connector. If you have a test light that can draw more current, then that is more definitive.

2. You have an issue with temp sensor A. It is possible that you switched temp senor A and temp sensor B when installing, because I think they are identical except for the temperature that the switch closes. Since they are new, see if the sensors have an identifying part number stamped on the metal. Alternatively, you would need to remove the sensors, heat water up with a thermometer, then use the continuity setting on your volt meter to see what temperature the switch closes.

 

So I have run the engine cold with the radiator cap off, no gas bubbles. I actually ran it a week ago when I was trying to get all the air out of the system, and no gas bubbles out of the radiator. Temp switch A was replaced by the mechanic before me, so I would assume he replaced it with the correct one. I'm gonna need to loosen it to see what the model number is. As for temp switch B, that was original. I replaced that one and found the new one using the model number off of the old one. Haven't checked the voltage on the condenser fan harness, will do that now.

 

Also checked the condenser fan harness. No 12 volts.

 

For the condenser fan, you need to move back to the relay. I think the 92 relay for the a/c compressor and a/c condenser fan are near the fuse box, but not in the fuse box. The 94-97 had them mounted on the radiator fan shroud. You may have to trace the wiring harness from the condenser fan to the relay, because I don't have a good drawing for the location. These 2 relays are larger than the relays in the box. To identify the condenser fan relay, one of the wires to the relay should have the same wire color as the non-black wire to the condenser fan.

Unplug the relay. Use a volt meter and hook the black volt meter lead to the negative battery terminal. With the key in the II position, 2 of the 4 pins should have 12V. The third pin will switch from open to ground to closed to ground when you turn on the a/c. You'll need to set you meter to continuity or resistance. The black meter lead will be on the negative battery terminal. The 4th wire should go from the relay to the fan motor and should be the same color as the fan motor.

Let us know what you find on this test.

 

So I found the relay, mounted between the power steering reservoir and washer bottle. I have 12v on 2 pins, the third pin does go to the positive wire for the fan, but I'm not getting a ground connection for the fourth.