Cooling fan relay sensor location is it above thermastat housing and rad.hose under throttle cables 2000 3.4 olds.

follow the upper rad hose from the rad to where it connects at the motor this housing the hose is fastened to this is where the thermostat is under the housing.

88? ,very old
what engine?
1.5 L EW5 (DA2)
1.6 L ZC(DA1 & DA3)
1.6 L D16A1 (DA1 & DA3) my guess, is the RAD fans dont turn on as the FSM directs?
and enging cooling question.
the fan is control by a relay and the cooling fan thermo switch
the relay white wire goes to the termo switch
the switch ground this white wire to activate the fan.
find.. i dont have the fsm only schematics.
the switch can only be 2 places on all car. in the RAD tank(look)
or on the water jackets of the engine.
my guess? see front of engine, front is #1 cylinder.
see main thermostat housing at 10pm?
to the right are 2 sensors, the one with a single with wire. bingo.
i see 2 ,secrewed in to cyl. head, there.

There are two things that may be the cause your cooling fans are not running. The first thing is the temperature control sensor, this sensor helps regulate engine temp in conjuction with your thermostat. The second thing is the fan relay switch. This controls both fans! The temperature contol sensor is attached on the driver side on the head, it is right above the bottom rad hose. The fan relay is probably attached to the body, they usually hide these under the plastic skirting in the wheel well!!!

The cooling fan relay is stuck,replace the relay

dont think so,seem to remember a reostat somewhere at the bottom of the rad right hand side ,check for earth problems as well ,sorry if vague but i seem to be forgetting things as i get old .

Check the rad fan fuse or the relay under the hood.
Is the temp going too high? Check and make sure you are not low on rad fluid (engine cool). An air pocket where the fan temp sensor on the rad is located will not activate the sensor.

Failing that, check the rad temp sensor which activates the fan. If this sensor does not close at high temp...the fan won't work.

Up under bottom cover under engine (cover needs to be removed) and your bottom rad hose is attached to thermostat housing, (remove it ) and thermostat is in behind that. Drain rad first, obviously.

The Coolant temp Sensor is located right under the top radiator hose (on the engine side), with a little black connector!, You might have to remove th etop hose to get to it with a deep socket and extension!.
Also Dont Forget to blled the coolant system by the bleeder valve uptop right near/above the coolant sensor!.(10MM Mini socket w/ extension IIRC!)

IS IT THE FAN RELAY OR THE THERMASTAT

normally this located by the thermastat housing if you follow the hose upper radiator hose to the thermastat housing there is a little plug with a wire on it and that is the temp sensor