Radiator Fan off and on, every 3 seconds

ratchet · Post by **ratchet** » Wed Dec 31, 2008 3:51 pm

Just picked up a 2000 ES with 92k all stock, having a issue with the radiator fan coming on and off every 3 seconds. I checked the coolant level in the reservoir, and it was empty. I filled it to the cold line and it seemed to stay there. I checked the radiator itself and there was coolant there. The ac seems to work, but its cold! outside. I am getting a sound from the passenger side (inside of the car) like the noise a blow off valve makes, any ideas on this?

Dave

Passt · Post by **Passt** » Wed Dec 31, 2008 4:13 pm

Is the noise constant?

ratchet · Post by **ratchet** » Wed Dec 31, 2008 4:38 pm

no, it comes on often enough to where its annoying.

Post by **occasional demons** » Wed Dec 31, 2008 4:52 pm

ratchet wrote:I am getting a sound from the passenger side (inside of the car) like the noise a blow off valve makes, any ideas on this?

Dave

I think that's the noise he was asking about. As in a possible vacuum leak?

Edit: try disconnecting the electrical connector from the back of the HVAC controls to see if the fan cycling quits. You wil need to pull the two vents out, remove two screws and the whole bezel should pull off. then remove the screws from the controls and remove.

ratchet · Post by **ratchet** » Mon Jan 05, 2009 7:36 am

ok, did what you said and here is whats going on.

I hear a click, and then the fan kicks on and then I hear the "shhhh" noise from the passenger side. It goes in that order and repeats every 3 or 5 seconds, could my ac be low on 134a, causing my ac compressor to kick on and then knowing it has none, it kicks on the fan which also makes that "shhhh" noise cause there is no 134a or does it sound like a leak?

Dave

Post by **occasional demons** » Mon Jan 05, 2009 12:52 pm

Your A/C shouldn't cycle if it is not in the A/C mode. It still does it with the HVAC connector removed? If so it could be your PCM is/may be gone, or possibly the coolant sensor. It will turn on the fan based on input from the HVAC and the coolant temp sensor.
Have you checked for any codes? (Key on three times, leaving it in the on position)

ratchet · Post by **ratchet** » Mon Jan 05, 2009 1:12 pm

yes it will still run even when I disconnect the HVAC connector. I just went out to do the key dance and no codes, just "done". Possible the coolant sensor is in the process of failing and hasent yet. Any other ideas?

Post by **occasional demons** » Mon Jan 05, 2009 1:29 pm

Just for shits and grins, pull the relays out in the PDC. If it still runs, then you have a short in the wiring somewhere. IDK if the high/low pressure switches in the A/C would cause this or not.
You would have to wait for someone that is more knowlegeable in HVAC. I do know that the fan normally is delayed from the compressor. and above certain speeds I think the fan operation is even cancelled.

2GN.ORG

Radiator Fan off and on, every 3 seconds

Radiator Fan off and on, every 3 seconds

Re: Radiator Fan off and on, every 3 seconds