Mechanics

CHEVROLET IMPALA THERMOSTAT PROBLEM

2003 Chevrolet Impala • 135,000 miles

Hello, I have a 2003 impala with a 3.4 motor. I am having a problem with the cooling fans not working properly. I do have a genisys scanner with 2.0 software that I just got. I hook it up and watch the temp on there. The fans do not kick on until 230 degrees and it is both on high. If I run the ac they both will kick on high for a few seconds at 217-220 degrees and the temp lowers a little then the fans shut off. I have checked all the fuses and they are good. I have switched the relays and it doesnt seem to change anything. The will both also come on if I unplug the coolant temp sensor. What would you suggest to find out what I need to replace. Thanks
Avatar
Lbowlingl19
March 31, 2013.




I would start with replacing the thermostat. Then monitor the temps.

Roy

ASEMaster6371
Mar 31, 2013.
Update: when I went back to check the relays I pulled them out and noticed that it is supposed to have two 4 prong relays and one 5 prong relay in the center and all three of mine were 4 prong. I bought the correct relay this time and put it in and watch the temp and the low speed fans kicked on at 217 degrees as thet should and all is well now. I hope this might help someone else in the future.

Tiny
Lbowlingl19
Mar 31, 2013.
Who replaced the relays? How did the wrong one get there?

Roy

ASEMaster6371
Mar 31, 2013.
They had to be like that when I bought the car. I bought it used. I switched them around with each other earlier to see if that made a difference and I didnt notice the prongs until I went back to check the voltage. Oh I changed the thermostat a few moths ago thinking that might have been the problem but it didnt change anything.
AD

Tiny
Lbowlingl19
Mar 31, 2013.
Are you sure you did not install the incorrect relay in the slot and the slot that took the other relay has the incorrect in there now?

Roy

ASEMaster6371
Mar 31, 2013.
No, I did check before I went and bought a new one. I now have 2 relays with 4 prongs and 1 new relay with 5 prongs

Tiny
Lbowlingl19
Mar 31, 2013.

AD