OK, within the past two weeks I've noticed three individual posts with questions regarding the A/C intermittently working, and cars temp gauges rising at idle. See below for pics...

Last summer I had both these issues:
Car A/C would not work at idle most times.
Car Temp gauge would raise significantly if car was left idling.

Of course I checked the most common causes for the problems.....and.....PROBLEM NOT SOLVED.

After much troubleshooting and 600 dollars in parts which DID NOT SOLVE THE PROBLEM (I purchased new fan motor, Fan ECU Module, and recharge of A/C system and new thermostat), I FINALLY FOUND THE ISSUE.

The wiring harness from the fan motor which plugs INTO the Fan ECU / Module is the issue.
We carefully took the harness apart to expose the wires from the fan motor that lead into the harness and the metal "prongs" they were attached to. I simply re-clamped them tight with a wire tool and placed them back into the harness. Plugged in the harness back into the Fan ECU/Module and PRESTO problem solved.

PLEASE, PLEASE check this BEFORE spending money on a radiator, A/C charge, Fan motor, Fan ECU, or anything else IF you are experiencing IDLE ENGINE TEMP RISING or A/C Working only when driving and not at idle or intermittently.

 

Could you post a picture of the area where the cable and connector is located? Appreciated.

 

Will do my friend. I will actually take some photos of the connector and the part that needs to be better secured to the wire.

 

Thanks. Was trying to imagine the connector you were describing... without luck. Problem when you get old.

 

It is lot easier to read about the problem afterwords and tell you that it is NOT the radiator and it has to be the thing that forces the air through the radiator when the vehicle is not moving -> fan or juice to the fan.

Salim

 

In the pictures below you will see the wires which come FROM the fan motors and plug into the Fan ECU. This is located just beside the coolant reservoir.




When disconnected you will notice the metal "tabs" inside the housing. Carefully take a pick tool and gently and slowly remove the wires from the housing. See below for the piece I am talking about taking apart:



The wires actually work themselves loose enough over time to cause a bad contact surface with the metal prongs within the wiring harness fitting.

 

My AC issue turned out to be a leaking radiator, a known problem on the 2004s. The car would run hot, but not boil over, and the logic in the AC system would shut down the compressor to help cool the engine. My dealer replaced the radiator and coolant free of charge for the second time (1st time was at 1 year old). It's been fine since.

 

I'm having the same issue w/ my '01 GS430 (231K miles). My mechanic checked both fans by idling at high rpm to heat up engine, he had a large diagnostic code reader hooked up, and both fans kicked on when engine got hot.

As he continued to press on gas the engine temp continues to rise even though fans are on. He said he "thinks" it's faulty water pump - - he said there should be more water pushing through to cool engine as fans are on and engine temp rising and it's not doing that.

My friend (engineer) thinks he's full of ****. I was skeptical too but he's had a pretty solid track record. Radiator was replaced 1 yr ago and no visible leaks or pressure issues, cap is okay. I was thinking thermostat?? But mechanic didn't bite on that and insists on faulty water pump. I gotta get timing belt + tensioner + spark plugs replaced so why not get new water pump (which was replaced @ 120K miles along w/ timing belt maintenance).

So were these fans working? Or not due to the bad connection? Maybe I need to show him this.

 

Elibutton, check the thermostat first if coolant levels are correct. Then water pump in that order. If fans are functioning, then your issue is water flow through and to radiator. Start with the thermostat. Then move to water pump. Then check radiator for clogs.