As the heading describes, i am at a loss now as to why my thermos wont run at all speeds.

I have an Ef xr6 for starters. I have replaced all relays with genuine ford parts from the wreckers (2 Sets) Fuses are all good inc Autotx fuse under dash. Changed over thermo fans which are both working fine, changed over to spare coolant temp sensor, changed thermostat (today), no fault codes present ATM, i have checked over the wiring which appears to be in good order.

Now here is where the fun begins. The fans kick into high speed only for a short time after starting the car and putting demist on high speed then they return to both operating at low speed. KOEO test kicks the fans on both at high speed when i engage a gear (manual).

So can somebody please guide me where i need to go.
I am pretty good generally when it comes to electrical on cars as i am a diesel mech, but this douche bag car has got me F*&@#D.

It will be the end of me if i dont get it fixed as it is affecting the performance, especially when i put the J3 chip as it pings its tits off through out the whole rev range due to it being too hot (detonation)

Assistance would be greatly appreciated.

Cheers Joel

So you've got yourself the wiring diagram for the thermos and done a point to point continuity test on them to ensure there is no breaks anywhere?

EF's have the gay 4 relay three speed system... Here's a pic I copied from the Ford book and possibly the pic from the Ford book...




If you have no breaks between the pins mentioned then all is well there... Then test the three trigger wires back to the EEC... Check for power at the three relay pins which have hard power to them... Also check the power to the coil wire is there with the key on...

If this fails, try swapping the EEC... You're 100% positive the fans aren't working? Don't work with the AC or anything? Car isn't just getting hot from a blocked cooling system is what I'm getting at?

Cheers,
Tim

I have the original Ford Manual on hand and have studied it quite alot with trying to figure out this problem.

When the ecu does the KOEO test it tests each relay to check for continuity all the way to the fans to pinpoint exactly which relay or fan that has a fault. As i stated no fault codes. I have had the no.4 relay fail before which i only diagnosed through the fault codes.

The fans only come on high briefly when i switch on the A/C then they switch back to both going at low speed. The engine was a full rebuild 30k ago and all new parts were used. Coolant is defiantly flowing properly all the way back to the reservoir as i watch it flow back to the tank. The heater gets hot and the coolant lines to my gas converter are also hot.

I fitted a 91 degree C thermostat today in place of a failing 88 Degree C. The gauge is sitting higher up than before i fitted the new thermostat so i know that the temp gauge is reading correctly. The engine bay temp is getting very high compared to when the fans where working.

It is definatly getting too hot as it pings on a standard tune as the ECU obviously cant retard the timing back far enough. Now the engine is worked to the s**t house inc high comp, but hasnt ran this hot before cause my fans were working properly at one stage after the build.

Cheers Joel

Ah ha... Awesome... Sounds as though you have worked at it...

Computer checks the fan circuit by use triggering each relay speed... So one relay for speed one, two for speed two and one for speed three... The two cannot be separated as they are hard wired together (same as the two in the EL)...

It checks the fan motors by watching for voltage drop on the car as they suck so much juice the voltage does drop, if the computer sees voltage drop then fan motors are recorded as working...

So it sounds like everything else is working... I'd be trailing a new EEC computer... Its the only thing left that could be causing the issue?

Only other thing is to put the inst cluster into diag mode and find what the computer thinks the degrees of the coolant is... See what it thinks it's reading... If it is reading 90degrees c and sitting there it wont bring the fans in... Even if the car is at 110 you know? Sort of a temp calibration out of sync type fault... I know you said you swapped it, but would be interesting to see what the computer thinks the temp is... How do you know it is getting hot besides it pinging? you have a second temp gauge? Or the car gauge is reading too hot or...?

Cheers,
Tim

Hi,

I have an EL, and the fans work in Diag but dont seem to switch on when they should. There are 2 wires going to the relay bank. I am thinking about cutting them and using a capillary switch to turn the fans on, so I can adjust the temp. Also, I would like to set them to run with the AC at low speed. I have found in the past that thermo fans slow the air when traveling at speed.

Even a switch on the dash for the fans will give you more time to fix it, without any risk.

Regards 96ELGli

Well a bit of an update,

I ran the dash in diagnostic mode and brought up the coolant temp reading and took the car for an extensive drive. The thermostat is defiantly working properly as the temp would hit 91-93 degrees then drop to about 87 at the lowest. I thought then that maybe i was going nuts and the fans are working correctly.

Of course the longer i drove it the engine would retain more heat, so at idle the engine would climb to 99 Degrees before i s**t bricks and took off to get some airflow happening. Now the other interesting thing is the fans kicked into high speed a few times while the temp was creeping up at idle when i put the aircon on full blast, then it just stopped going to high speed and would return to the one speed only for both fans.

If i were to switch the car off then on again the fans *may* and that's a BIG may, come onto high speed then return to the usual trick of no high speed at all until i restarted the car. Im am now poiting towards a new ECU.

Reason being because the car is very erratic with its "power performance" one minute its going all guns blazing, i switch the car off and restart and its very flat. I have had numerous people confirm this to me who are regulars in my car. Same goes when i pop in my J3 chip, it will go hammer and tongs, then it decides it doesnt want to play ball. I've spoken to Jason from T.I about this but it keeps getting put down to bad connections. Im now being led to believe my ECU has gremlins.

So if anybody know of anyone selling a 4TAB-C or D ECU i am in the market for one.

Cheers Joel

Hey does anyone know exactly at what temp the EF fans are meant to kick in.

Just want to cross reference this to the activation of my fan relays.

Cheers Joel

Don't know the temp when they actually kick in - the ECU gets a multitude of inputs that vary that.

Coolant sensor resistance:

2.2 kohm 98 degress C *
2.0 kohm 102 degress C *
1.8 kohm 105 degress C **
1.65kohm 108 degress C **
1.3 kohm 116 degress C **

* fans on low speed, ** fans on high speed

Pulling the sensor plug off will make fans run at high speed (be careful with the belt)

I am having a problem with the cooling fans as well, but it's only my left one that isn't working. I WAS going to replace the fans as I assumed a burnt out motor in the left one, but then I picked up one of {DESCRIPTION} because I had some other things I could use it for as well. Well, after checking the fans by supplying voltage to them, the fans actually worked fine! Which leads me to think its a relay/continuity issue



So would this mean that if one of the relays wasn't working, it would come on with a separate code? Because I'm getting code 778 (Electric fan 2 operational fail (Passenger side) Fan motor not drawing current from battery when switched on by EEC during Self Test.) If it was a relay would that have a separate code?