Billiamch

Coolant on my es300 started boiling and temperature gauge wasn't going up. Followed instructions on another page for diagnosing the problem, tested radiator fan switch and results suggested changing the switch/sensor. Did so, fans still don't work unless AC is on. I'm thinking it could be another coolant temp sensor or radiator fan switch. Anyone have any suggestions? I'm in a bugger because I'm in college and depend on my car to get me to class 40 miles away. I also checked my thermostat and it is opening and closing properly.

also, father thinks 35w HID bulbs are causing my cooling system to fail. Ive isolated that is NOT the cause. Unless anyone has any suggestions or experience with that, let me know!

crwys

Your car shouldn't be over heating while you are driving. Fans usually only come on when you are idling.
I have an old 89 honda. When I bought it the fans didn't work. I drove it for almost a year and never had any over heating problems unless I idled too long.
But to address your fan problem. I'd also see if you have any similar relays you can swap with the fan relays to see if that's the problem.
There is two fan switches. One on the radiator and one on the engine.

You might have a clogged radiator or failing water pump.

Edit oh lol. Nvm. (Was going to say thermostat)
Actually what I will say about the thermostat. If your heater isn't blowing hot air, I'd say replace the thermostat. You sound pretty capable of testing these things, but if you are not sure about diagnosing the thermostat. I'd say replace it any ways, it's cheap.

Billiamch

I just had my water pump replaced by a shop in town with some oreilly's ****. Wouldn't surprise me if it failed after 2000 miles.

LeX2K

You did this test?

crwys

That would be a shame if it failed that soon. Definitely not likely. But that's pretty much all I can think of.
Thermostat
clogged radiator
blown head gasket
water pump

Hope you get it figured out.

If the car is over heating while you are moving I wouldn't worry about fixing your fans for now.

Billiamch

I performed that test under my father's direction. Looking at the diagram, the pictures don't match up now. Is the ECT1 the connector on the top of the driver side of the radiator or am I mistaken?

Billiamch

you WOULDN'T worry about fixing the fans if it IS overheating while driving?

crwys

That is correct. Like I said, fans are only used when idling to pull heat off the radiator. While you are driving the air from the outside is being pushed through your radiator as you are moving essentially performing the same function as your fans.
You have a different problem to worry about, fix that first and you'll be good to drive and you can fix your fans on your own time with no big rush.

MichaelPm

Happened on my Toyota Celica was a simple relay I pulled from a junk yard and it worked