mx5-kiwi

Hi Guys, just completed a M tuned coolant re route. Did a warm up and no leaks so far...

Problem is rad fan won't kick in despite the link ecu saying active (and unactive when threshold raised manually).

So I have ECU temp reading, I also have a dash gauge reading. I followed the instructions to lengthen the ECU leads and believe I did it right (i presume this to be the case as the link is getting the temp reading).

Where does the fan gets it on/off from....any thoughts on what to check.

Cheers.

Oscar

iTrader: (2)

Did you by any chance remove the sensor in the front waterneck?

olderguy

iTrader: (19)

The 1.6 NA's through 1993 used a sensor(thermoswitch) in the front thermostat housing to activate the fan relay. Nothing went through the ECU. Grounding that single wire turned on the main fan.

Oscar

iTrader: (2)

Hence my question

Joe Perez

iTrader: (8)

Yup.

mx5-kiwi, on the '89-'93 engines (in the US, at least), the cooling fan is not controlled by the ECU. It is controlled by a mechanical thermoswitch which is mounted vertically on the front thermostat housing. When this switch gets hot, it closes, which grounds the black/green wire and activates the cooling fan relay.

If the car has air conditioning, then it is impossible to control the cooling fan from the ECU. There is a wire which runs from the fan relay to the ECU, however this is the same wire that the ECU uses to turn on the aircon.

If you want the ECU to control the cooling fan, you'll need to splice into the black/green wire and bring it to the ECU, then connect it to the fan driver. I'm not familiar with the Link ECU, so I can't provide specific details on this.

Otherwise, just find a place in the system to re-install the thermoswitch that you took out when you removed the front upper thermostat housing. You could drill and tap the front blockoff plate and install it here, although installing it in a location towards the rear of the head (near the ECU thermosensor) will provide more accurate operation.

mx5-kiwi

Hi Guys, you are correct I did remove the front housing. I reinstalled the sensor that was in it back in to the new block off plate. Could the fact that the plate is aluminium create ground issues...?

I was under the impression the ECU sensor at the back fed the vehicle Ecu and the front sensor fed the dash gauge, I haven't seen anything else to provide a switch for the fan itself other than the sensor for the dash gauge, is there physically something else?....

Braineack

iTrader: (62)

if the block off plate is not actually touching the head and is insulated from a gasketing material maybe.

Zaphod

Yep, this is it, yoi need to ground the spacer. Had this too..

mx5-kiwi

Sweet, i'll try this. Thanks guys,I would have spent forever chasing this!

mx5-kiwi

Okay, still no go. Had an electrician check it and the fan and switch etc are fine. It would appear that the fron location is not getting hot enough to activate the fan....

1- Is this a problem to worry about.
2- Could this be associated with having the thermostat down the side of the engine and not at the back as per the instructions? (about 10" from the back adaptor not 2-3 as the instructions suggest). RHD made it difficult to put where suggested due to clutch hard line coiling around that area....

hustler

iTrader: (6)

Just put the thermoswitch wire on an output triggered at 200*f like my car.

kfed

Having the same issue, didn't know that wire was a mechanical ground. I tried wiring that connector to my aftermarket gauge's sender, but obviously that's not a ground. I'm gonna try and ground it and see if anything happens.

Also, my stock gauge is pegging hot but my aftermarket water temp is reading correctly (obv). I also tried putting a paperclip in GND + TFA and all I hear is the relay clicking but the fans don't turn on.