Phase 3 cooling fans

[Pompeymj]

Hi all, I'm new to this forum and I've been trying to help a friend with his recently purchased Y reg 1.4 306.

I've read through this guide http://306oc.co.uk/forum/thread-7432-post-150325.html and we can follow all processes up to the coolant sensors. The pair of us have been able to spot the location of the three coolant sensors. We have one blue one on top of the thermostat which if we unplug turns on the nearside fan (I assume at full speed, I've had nothing to compare it to). We pulled out the offside fan to test it directly off 12v with no response, I assumed it was a dead motor. We picked up a second hand one which also failed to spin off 12v... Another dead one perhaps? We also can't spot the bitron unit (we had the bumper off at the weekend).

I've tried numerous relays with no change, all fuses are intact, the thermostat is fine, the radiator was replaced prior to his ownership on which we noted an additional blue sensor but no wiring harness connection?

Any further guidance or things to try? Failing that we will install an aftermarket fan on the inside of the engine bay.

Thanks in advance. Mike.

[Niall]

Hi Mike and welcome to the forum.
Biggest thing we need to know is does this car have air con? (won't work being a 306 but does it have a AC button?)
If so, you should have 3 sensors on the thermostat housing.. Blue, brown and green. The brown one is the temp switch for the bitron unit which controls the fans. With the engine running, if you unplug the brown one then within about 5 seconds both fans should come on full. If not, this is an issue with the bitron, fans or wiring. Basically it just proves the sensor isn't likely to be at fault.
The bitron is located under the chassis leg under the passenger head light and is a black box slightly bigger than a pack of fags. Theres no way to test this other than how i described above so only way really is replacement.
The first thing i would check is the round multi plug on the passenger side connecting the fan unit to the cars loom. These are notorious for corroding and can even cause fires! Unplug it and any sign of corrosion, clean it up with some lighter fluid and try again.

[Pompeymj]

Thanks Niall, yes it is an AC model (forgot that bit). I'll post a pic of what we have and maybe someone can fathom it out. From memory there is only the one blue connector over the thermostat.

As for the large circular connector it's clean, not corroded and we took a complete cowling with loom, hooked it up and had the same result so I assume the loom and relays are ok by elimination.

[Pompeymj]

Niall,

This picture shows the area in question and you can hopefully spot our dilema.

Mike

[Pompeymj]

Does anyone have anything to offer on this? We are tackling it again on Sunday. Mike

[cully]

does help if you state which car model, engines type, aircon or no and age
as there are different cooling fan set ups throughout the range

[Pompeymj]

Cully,

All of that info is above... Y reg 306 1.4 meridian with a/c, manual box. Single temp sensor on top of thermostat as above picture. I don't have an engine number to hand.

Mike