Hey all, was driving today and noticed fans arent turning on when at the right temp

Earlier today all was working fine but now it isnt?

Ive attempted cleaning out all of my relay and even swapping my ac one with the radiator one, still no direct startup at temp, ive tried hair pinning A & B from the terminal, makes an odd noise but again doesnt turn on.

Ive tried a hair pin from the red wire to the black and red wire in the relay which DOES WORK and activates the fans but as soon as i remove the hair pin they go off

Ive also tried sending volts/grounding the green and white wire in the relay, but this doesnt click or turn the fan on

Ive also checked the coolant temp, when i took it out the fan turned on for a millisecond which weired me out and made me think its related to that?

Im curious on what the issue is, and if its something to do with the green and white wire and if i need to replace it or if its something related to a thermostat issue or coolant temp sensor

Im somewhat amateur in this area so any helps appreciated!

 

Welcome to the forums. Electerial can often be a head scratcher. Check all fuses first, then locate the fan temperature switch. there are three. One is for the gauges,the second is for the ECM and the third is for the electric fans. On your model I'm not sure of exact locations, one or two are usually located by the thermostat housing and the other could be located in the cylinder head or heads between 1 and 3 cylinders between the exhaust ports possibly. When the temp switch is located pull the wire, with key on the wire should read 12 volts and when grounded it should engage the relay and turn on the fans. The gauge wire when grounded will peg to hot side when grounded, and the ECM temp wire will turn on your check engine light and engine might not run. The HVAC on defrost should also turn on the A/C compressor and fans, that manually overrides the engine temperature sensor. I think your fan temperature sensor switch could be bad. With the engine getting hot the temp fan sensor should be grounded, check using a light or miti-meter. Good Luck. Let us know what you find out.

 

yilly: welcome to the forum.

 

Hey Yilly, did you ever get this fixed?

I realize it's been a year but I just went through this on a 1986. It turned out that under previous ownership the fan motor must have gone bad and drawn too much amperage, mostly frying the fusible link but not all the way. This confused me because I got voltage at the fan supply plug, but not enough amperage to spin the old fan motor or a new one. After replacing the relay and the fan motor, I soldered in a new fuse in place of the old broken fusible link and everything worked.

Here's a link to my forum thread on it:
https://www.corvetteforums.com/forum...ont-run-20811/