Help cooling fan

[LTC67]

My 1996 LT4 has cooling fan problems they will not come on 228 deg, the 3 relays are all good and fans are good. If I disconnect the temp sending sensor the fans will run at high speed. chgd everthing except ecm?

 

[vetteoz]

Do they work if you turn A/c on ?

If disconnect the temp sending sensor the fan will high.

Please explain

 

[LTC67]

yes they do work with a/c

 

[vetteoz]

yes they do work with a/c

ECM turns fans on when A/c on; regardless off engine temp
If they work with A/c on then wiring from ECM to relay must be right .You say fans/ relays work so it must be a control problem in that ECM is not sending the signal to turn fans on.

Have you confirmed the reading you are seeing off the temp gauge when fans not turning on is the actual engine temp ? gauge could be faulty

If so 1st guess would be ECM is not seeing correct temp reading from engine.
Faulty coolant temp sensor maybe

 

[LTC67]

I have put two new sensors on I will chg ECM just wanted to confirm before buying one. Hope this does it wife is really getting impatient with this parked car.

Sure do thank you for time,

Larry

 

[Fast Freddie]

i would get someone with a data scanner to confirm actual temp. guage may be off a bit. i'm pretty sure gauge and ecm use 2 diff temp sensors...

 

[LTC67]

Thanks I guess a Tech II will do it

 

[vetteoz]

I will chg ECM just wanted to confirm before buying one.

As noted would do other checks before shelling out for new ECM.
ECM is obvious controlling the fans correctly but is just not getting correct input to do so IF your temp gauge is accurate.
A OBDII scanner should show if the ECM is seeing correct readings from Coolant Temp Switch which sends engine temp to ECM for it's operation