Overheating problem, fans not running when up to temp.. Temp. sensors okay, where is ECU IG fuse located on this car.
Having a problem with the cooling and condensor fans, heating up problem on my 2001 ES300 lexus,, the temp sensors seem to be okay, I want to check out the ECU IG fuse, then on to the relays, the problem,, the car will get hot if sitting still because the fans are not running,, this is in the phoenix az area. I removed the temp sensors and checked them out by heating them up,, they are doing what they are supposed to do.. where do I go from here.
A 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
The service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones). click here to download the app (for users in the US for now) and get all the help you need. Good luck!
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
check terminals on the ECM
the circuit is when the coolant temp sensor ( not the gauge sender) reaches a predetermined setting , power is supplied to the ECM which in turn activates the fan relay and switches on the fan
there are normally 2 fuses in the circuit
the gauge sender is normally a single wire unit and the sensor unit has 4 wires to it
a few things to check here. You need to find the short it could be anywhere between your fuse and the motor for the fan (fans) itself. There is a temperature sensor that controls the fan it may or may not be separate from the one that displays the temp of your coolant on your instrument cluster.
The temperature sensor may be controlling the fan via a relay; these can fail by welding the contacts together remaining permanently 'on.'
Locate the fuse (and possibly relay) box, check inside the cover for a layout that identifies which fuse or relay controls the fan; they are often on their own fuse and definitely on their own relay.
The 2 AC fsnd turns on when the Engine temperarure hot. It receives the signal from ECU throught the Engin temperature sensor ( Coolant). Your case happens since the Engine Temp sensor went bad. At beginning the temp sensor can not produce any resistance just like open then ECU thinking engine hot turns on the Fan. When your engine ia about 85, it is a normal temp then the sensor could produce some resistance matching the look up tabel for the ECU, then the ECU turn off the Fan. Some pepople has it run all the way since the wire contact to the sensor was off. Replace the Engin Temp sensor to take care of the problem.
You have 2 temp sensors on top engine, one for your temp read out, one for the fan purpose. If you don't know which one, wait for your temp at 85 and the fan is stopping, then unplug one, imediately the fan goes on, that the one. Good luck.
Cooling Fan Temp Sensor is the First thing You Check (with what you have described) Cooling Fan Should ALways come On When The A/C is turned On as A/C Adds A Load to Engine, If Temp Sensor is Faulty it Will Not Give GROUND Signal to ECM >For COOLING FAN >RELAY to Give ground and turn ON The Fan.
There ARE 2 temp Sensors that Serve Different Purposes 1 is for Dash READING GAGE & Or TEMP LIGHT the Other is For ECM or Fan Relay (SAME Thing) you Said>""can disconnect the sensor and fan continues to run" < This Leads me to think you Changed the Wrong One. Not Questioning your Skills Just Here to Help.
TEMP SENSOR FOR 3.1L V6 is Located upper RH rear of engine compartment, near exhaust system. Temp SENSOR for 2.3L Engine is Located in LH rear of engine compartment. I Hope this Helps Lead you to a NON-OVERHEATING Pontiac.
Good Luck and Have A Great Evening. rejakwilson
there are actually 3 temp sensors. 1 is on the top of the engine that goes to temp gauge in dash has 1 wire. next to it is a 3 wire sensor for engine control and choke. on the bottom of the radiator next to the hose is a 2 wire sensor. loosen all 3 but leave connected. get engine hot past halfway point on dash gauge. with ac off disconnect 1 sensor at time. start with 2 wire under radiator. it takes the most abuse. fan will come on when you disconnect broken sensor. 2sensor must agree for fan to stay on till engine cools when turned off. note this is solution i used after verifying fuses, fuseable links and relays worked.WOO HOO! make sure you check both the fuse box under hood and fuse boxleft side of steering wheel my ECU fuse was inside my bros was outside.ECU B on my car goes to nothing and is under hood. Had it confused with ECU on wiring diagram.DOH!
You should check the 30 amp "RDI" fuse and the 7.5 ECU-IG fuse. Both fuses are critical to the operation of the fan system. The RDI fuse sends power to the fan #1 relay. The A/C amplifier turns on power to the fan #1 relay, this is why your fan works on A/C.
Now, with no cooling fan under "normal conditions" (A/C off), you need to have a good fan #2 relay, and a good water temp switch. This switch is on the engine, near the thermostat housing (I think); with a single plug, with a white with a blue trace wire going to it. Remove this wire from the sender, and jump it to ground (anywhere on the metal of the engine) with the key on (engine OFF). If the fan starts, you need a new water temp sending unit. If not, then consider a new fan #2 relay. This system is pretty simple.