I've changed all the relays, no joy. I changed the temp sensor(red one} no joy. I unpluged the connector to the temp sensor (no joy) Reset the computer, No joy. Cleaned the connector to the temp sensor, no joy. Any suggestions anyone, I read all the threds concerning this and still no solution.

 

Did you replace the coolant temperature sensor with a new one?

 

Did you follow commander Heatherly below after he lost sight of you and called no joy?

 

replaced coolant temp sensor, still jacked up.

 

Are both fans literally on all the time? Even on a cold start?

 

Stuck relay, or jacked up wiring, check coolant temp sensor connector as well

 

I assume it's VG30E auto.

How did this start? Are there any other problems which started at the same time?

What is your battery voltage?

Just to make sure we're talking about the same sensor - the one which controls the fans is shown on top of EF & EC - 12 page of FSM.

Can you measure voltages on pins 6, 19 & 28 of ECU while ECU is connected and key is in ON position? You'd need to use some needle to reach the contacts.

 

is your AC or defroster on?

 

disconnect ECU connector. measure resistance between pins 28 and 30 on the ECU (See EF&EC 91). you should have ~3kohms on a cold engine and about 300 ohms on a warm engine.

If you have an open circuit, then check resistance of the coolant temp sensor to make sure it's working (yeah, I know you replaced it. you sure you got the right one? I've seen stranger things happen). If it's working, then you have other problems- probably related to the ECU.

 

Mine (VE30DE) doesn't depend on those - fans stay off regardless of AC/defrost and engine running or not. May be it would behave differently if it was summer

 

I second this guy's problem. I have the same but haven't worried too much about it as the car does eventually get to normal operating temperature. Still though if its an easy fix i'll do it

 

Can you do at least what Matt93SE asked above? This would allow at least to see how CTS looks from ECU point of view. It is possible to replace part by part until you hit the faulty one but you need access to those parts and know for sure they work: fan relays, CTS, ECU. Doing electrical measurements allows fixing this kind of problems without extra parts. It's up to you.

 

Then you have a failed fan or ECU or relay.
the fans are supposed to automatically come on low when you turn the AC on in order to pull air through the condenser coil so the A/C works properly (it's not for engine cooling purposes... the ECU turns the fans on high when the engine starts getting hot).

 

Thanks - I'll check it out.

 

How many ohms should a CTS read disconnected?

 

fans are on at start up until shut down.

 

i call defective relay. give it a tap/wiggle and see what happens.

 

go reread my posts and ask yourself that question again.

 

Any joy yet? I've got the same problem with my '94 and hope to solve it.

Thanks,

Mike

 

I found the service manual in pdf HERE.

 

Hey Gents, I back from a short deployment. I got it fixed. The connectors to the temp sensor was corroded deep into the connector's back shell. I cut it off and spliced another one in from one I got in the junk yard. All the post were great and I appreciate the help, Now my power door locks are acting up on the 05'MAX.

 

Resurrected this thread to record my experience with the same issue.

Exact same thing as cspangg happened to me. Had the timing belt and drive belts done and when I got my 91' back the fans where on high speed all the time. Mechanic must have jostled the water temp sensor connector on the firewall side of the "V pipe" the feeds temp data to the ECU. It had corroded contacts and I could wiggle it and the fans would spin up and turn off. Had to spray the crap out of it with CRC and scrape the contacts with a little knife and now they're functioning normally.

This link is helpful:

http://www.cardomain.com/ride/748507/3

About 1/3rd down the page is info about the water temp sensors.

 

I also had corroded contacts on my CTS. I replaced the sensor, but after scraping the terminals on the old CTS with an x-acto kinfe, I now have a spare sensor. The radiator fans on full blast as soon as the key was turned (on a cool engine) led me to the CTS.