Radiator Fan Not Turning On

[motoservdog]

Hi all! Got a problem with my 95 Camaro 3.4L. The radiator fan is not turning on at any temp level. I read somewhere that the fan should turn on at 220*, the engine temp on my car rose to about 260* yesterday and I opened the hood to see if the fan is working. My Haynes manual said check the fan, relay and temperature sending unit. Fan worked when applied with 12V directly, fan relay tested good, no continuity between pins 1 and 4, unless voltage is applied to pin 5 and pin 2 is grounded, then continuity is there. I also checked the socket of the relay, Haynes said socket 1 shoud always be powered, socket 5 powered only when key is in the "ON" position. Checked out ok except socket 5 had very low voltage, not like socket 1 which had ~12V. Haynes did not mention ho many volts each socket had to have. I then checked the temperature sending unit. Haynes manual said that resistance of the sending unit should be ~1300 ohms when engine is 100* or below and around 55 ohms when 260*. I did not get this and am assuming the sending unit is defective. My question is, will a defective sending unit not turn the fan on? The temp guage inside the car is working fine, tested it also by grounding the sending wire. The guage went to full swing, indicating that the wiring and he temp guage are both working. Need help as I just had my engine rebuilt and don't want to mess it up due to overheating. Any suggestions? TIA.

[landj]

Re: Radiator Fan Not Turning On

Okay, I checked with my 95 3.4L You should be getting a full 12 volts on socket 5 when the ignition is on. (that's what I've got). I would work your way from the back of the fuse box to see if you can find the short or loose connection. It could be something very simple. Just take your time and keep following the wire back from socket 5 and probing for +12 when the ignition is on. Oh, and don't short anything out.

[motoservdog]

Re: Radiator Fan Not Turning On

thanks. it was the engine coolant temp sensor. all is good now.

[landj]

Re: Radiator Fan Not Turning On

So your gauge displayed the "correct" temperature, but the fans didn't kick in?

[motoservdog]

Re: Radiator Fan Not Turning On

yes. there's two sensors on my 95. one is the engine coolant temp sensor that sends the signal to the pcm. the other is the one that sends the temp signal to the guage.

[tkoforpresident]

Re: Radiator Fan Not Turning On

both my temp sensors are new but i'm having the same prob u are, any chance u could help me step by step to figure out which part of that process is broken? I've never really checked things that way before.

[motoservdog]

Re: Radiator Fan Not Turning On

check the fan fuse, fan relay(s) and the fan itself.