Hi everyone. I have an 85 vette that had a new cooling fan motor put in about 6 months ago. Well, now the fan will not kick on. I didn't notice it until I got into traffic and things started to get hot. The fan motor should be good because it is new and the fuse in the box is good. What is my problem? Need to know the location under the hood of whatever needs replacing too. Maybe a temp sensor??? I really don't understand this part of the car so any help will be greatly appreciated. The coolant temp went up to 240 so I pulled ouot of traffic and opened the hood and the fan was not running. Thank you again for any help.

 

Do you have one or two fans?, if you have two one is located on each side of the radiator.

Could be a temp sensor or it could be the relay.

Let me know how many fans you have.

 

The main cooling fan is controlled by the ECM. To test the ECM and relay, you can jump the "A" and "B" terminals of your ALDL, the ALDLis located under the dash on the drivers side, with the key "On" engine "Off". That should run the fan.

If the ECM fan control test above fails, test the relay by jumping the Dk Grn/Wht wire (at the main fan relay) to ground with the keyon and the main fan should come on.

The fan relay is located under the hood on the drivers side, it's mounted to the side of the tire well near the battery.

If the second test fails, unplug the relay, you will have 2 small wires and 2 larger wires. Take a jumper wire and jump the 2 large wires with the key on engine off, if the fan is good it will come on.

Here is some info and a wiring diagram for the main cooling fan

http://members.shaw.ca/corvette86/Co...%20Control.pdf

 

I think I found the problem guys. The shielded wire that connects to the coolant temp sensor that is screwed into the right bank cylinder head was broken at the connector to the sensor. It looks like someone tried to solder the wire into the sensor. Am I right that this could be the problem??? To answer the question of one fan or two, I only have one. Thanks for the replies.

 

Ok guys, reconnecting the wire to the temp sensor didn't work. I tried the ecm test grounding a and b and that didn't work. Going to an Alice Cooper concert right now so don't have time to do the other test right away. I keep asking myself what would happen if I just wired the fan to run all the time??? I've had it with all of these sensors that make things kick on when GM wants them to. I'll do the other tests when I have time. Thanks Shiver for your info.

 

Fix it man!!...don't straight wire it.

 

I'm gonna fix it. Just venting frustration. I just hate electrical.[:@].I wonder why they didn't just put a clutch fan in these cars like in my chevy truck.

 

I know the feeling, just go through the process of elimination and you'll find your problem.

I would guess the reason they didn't mount the fan on the motor is because the fan would eat up a few horses. Personally, I would rather have the electric fan, especially idling in traffic. Also the fan shuts off when it's not needed. The fans onmy 85don't even come on unless the AC is on or I'midling in traffic.

 

Hi everyone. Just an update. I tried all three tests and they all failed. However, jumping the green and white wire to ground made the relay click and so did the ecm test. Jumping the two large wires at the connector to the relay didn't do anything though. If all of these tests failed, does this mean I have a bad motor??? I just replaced that motor six months ago. It's brand new. I also checked the fuse in the fuse block for the cooling fan as well as the fusable link in one of the large wires at the connector to the relay. I still have not reconnected the wire to the temp sensor that tells the fan when to come on. I have to get a new connector for it since someone gobbed solder all over it. Just wanted to see if the motor was faulty first.Would this make all of these tests fail? Thanks for all of your help rshiver.

 

If the ecm test activated the relay, do the test again and check the voltage coming out of the relay. If you have voltage from the battery going into the relay and no voltage coming out of the relay, then the relay is bad. If you do have voltage coming out of the relay to the fan, check and see if you have voltage at the fan motor.,I f you do have voltage at the fan, and the fan doesn't come on, then the fan motor is bad.

Edited to add...Be sure to checkthe connectionat the fan and make sure it's plugged in good