pcm fan signal too weak?

[chvz99]

my relay is making a buzzing noise when trigger by the ecm , the fan will come on relay gets hot .
i triggered by applying ground to it and it will work fine no buzzing .
what can be that when trigger by ecm it buzzes. seems like if the signal was weak.

[redaddiction]

my relay is making a buzzing noise when trigger by the ecm , the fan will come on relay gets hot .
i triggered by applying ground to it and it will work fine no buzzing .
what can be that when trigger by ecm it buzzes. seems like if the signal was weak.

Did you build your own harness or buy one?

[vortecyota]

Go into to the tune and set the a/c recirc output to cooling fan cntrl.

[chvz99]

its a gmperformance harness.
even if i disconnect the fan from the relay when the ecm sends the signal the relay will buzz.
and if i ground the relay to it will run the fan normaly with no noise on the relay or it getting hot.

[TXSZ66AVLANCHE]

What year is your truck? If you have a 99-02 the pcm triggers the relay with voltage....not ground.

[chvz99]

the truck is a 99.
the ecm im using is an e67 with an 08 tbss system.
im thinking my tuner set the fans settings as pwm corvette style instead of ls1 (relay controlled) thats why my ecm ground signal is making the relay buzz. basicaly on and off. relay gets hot an eventually burns. he will have to check the program and make the changes.

[farmtruc]

What year is your truck? If you have a 99-02 the pcm triggers the relay with voltage....not ground.

which pin are you referring to? low speed is ground triggered.

[chvz99]

blue connector e67 pin 54
and gray connector pin 49
it does send the ground signal but the relay will start buzzing getting hot.
and if i apply ground to the relay where the ecm wire goes it will not get hot or buzz.
it migth be that he set them up as pwm and not ls1 style. i just havent got a hold of him.