Overheating... Fans Do Not Come On

[gaydm.accord]

ok one of my buddies asked me to fix his car. the problem is its overheating and the two fans infront of the radiator do not come on.

first thing i did was make sure that there was no air in the system... check

then i took off the thermostat and it looked pretty corroded and tore up so i took that out but it was too late to get a new one so one will put replaced tomorrow.

i then disconnected the fans and checked for power... theres power going to it but the fans do not come on after idling for quite a while but i do notice that it will go on when the engine first starts but that only lasts for 3 seconds and it wont come on after that.

i am thinking that the coolant temperature switch is faulty causing the fans not to kick on... but then again even when the ac is turned on the fans wont go on either... after searching the forum and google i couldn't come up with any temperature sensors for the ls400. fresh out of ideas please help.

[eXOBeX]

I take it this is an LS430, not an LS400 (I've looked through Toyota's Electronic Parts Catalog and the LS400s appear to have a single fan that's driven by the engine).

The fans are controlled by the "cooling fan computer" mounted nearby. Look for a small, finned block that's mounted at an angle near the radiator. Part number is 89257-30040, fits LS430 from August 2000 onwards, and nothing else. Worth checking its connections.

Also there's a temperature sensor down to the left of the throttle body as you're looking from the front. Apparently it's a water temperature sensor for the E.F.I., but other stuff might read it, too. Parn number is 89422-30030, once again it only fits the LS430.

Hope this helps.

[gaydm.accord]

I take it this is an LS430, not an LS400 (I've looked through Toyota's Electronic Parts Catalog and the LS400s appear to have a single fan that's driven by the engine).

The fans are controlled by the "cooling fan computer" mounted nearby.  Look for a small, finned block that's mounted at an angle near the radiator.  Part number is 89257-30040, fits LS430 from August 2000 onwards, and nothing else.  Worth checking its connections.

Also there's a temperature sensor down to the left of the throttle body as you're looking from the front.  Apparently it's a water temperature sensor for the E.F.I., but other stuff might read it, too.  Parn number is 89422-30030, once again it only fits the LS430.

Hope this helps.

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thanks for the reply i forgot to mention its a 91 ls400

[eXOBeX]

With twin electric fans? Don't know, then - on the Toyota EPC that model's got a single fan, driven by the engine. Checked USA, General, Europe, even the Japan discs (the Celsior had a hydraulic motor instead of an electric one!)

Have you asked over on the US forums?

[gaydm.accord]

With twin electric fans?  Don't know, then - on the Toyota EPC that model's got a single fan, driven by the engine.  Checked USA, General, Europe, even the Japan discs (the Celsior had a hydraulic motor instead of an electric one!)

Have you asked over on the US forums?

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yea i have asked on the us forums.

any how i took the car into my shop that im taking for certificates. we ran the diagnostics tool and the car is at perfect running temperature. then we disconnected the temperature sensor. found out that the needle would drop but not all the way down to the c but one bar above. our conclusion is that the needle shifted some how and needs to replace the temperature gauge.

as for the fans. it runs on 1 single hydraulic fan(your right i was confused and now i understand what you were saying) but on the other side of the radiator theres 2 more fans that dont come on. (when ac on the fan SHOULD come on but doesnt, it only comes on when we first start up the car and then shuts off after 3 seconds.)

will have to look further into the relay and test it out. any other suggestions is greatly appreciated.

btw thanks for the reply.