12 replies to this topic

[Neil1275]

Hi All 

 

Have looked at many posts on this fault and done some research, seems to be a common fault, will run trough what i have done so far to try and sort out why radiator fan not working.

 

Would like to fix it before it goes to bodyshop. 

 

So have checked fuse, all ok, then up to relay, 12v power at the purple wire, power at light green/black wire from ECU.

 

Removed relay, live and earth to 85 & 86, relay clicking ok.

 

I have a power probe connected to battery, i put 12v feed to black/green wire, fan runs ok.

 

Has had a new temp sensor, but temp on dash only goes up to half way, overheats, fan not running.

 

Do we think this is a faulty new sensor or is it advisable to do the temp sensor wiring plug mod?

 

Any advise would be great.

 

Neil

 

 

 

 

[Quinlan minor]

Does the fan work if you power it directly?

[cal844]

Does the fan work if you power it directly?

OP said it does

[Neil1275]

Yeah, when i power probe 12v to black/green wire fan works. 

[Quinlan minor]

 

Does the fan work if you power it directly?

OP said it does

 

Apologies, missed that. Definitely do the mod on the sensor wire.

Does the fan run if you disconnect the water temperature sensor?

If you have a multimeter, check the resistance on the sender when col, normal and hot and see what values you get.

[Neil1275]

No fan does not run when disconnecting temp sensor.

 

Will check that and see what values i get, cheers. 

[Quinlan minor]

The fan should kick in when the sensor is disconnected. That was the pre-modification wiring. The cable was too short and, under tension, would fail, which meant the fan stayed on all the time.

Check that both wires are continuous and that there is no (electrical) contact between them.

[Neil1275]

So today have removed ecu and checked continuity of Pink/Green & Pink/Black wires, all ok.

 

Also reconnected everything and have 4.9v at Pink/Green sensor plug & Earth at Pink/Black sensor plug.

 

Temp sensor when cold 1.848 Ohms

 

Wondering if this is all down to Temp sensor plug not contacting sensor, will order modified one and fit it to eliminate that.

 

The fan has never run, even if you disconnect temp sensor.

[Neil1275]

Update 

 

Have fitted wiring mod with new plug and fan still not coming in, also temp gauge only goes half way regardless of temp.

 

Could it be faulty new temp sensor? Thermostat? all hoses are hot. 

[Cabriomin]

Simple airlock in the system? Changed the coolant recently?

[Neil1275]

Yes is new coolant, all hoses including heater gets hot.

 

Left cap off for a few days as car is stripped inside and out for bodywork and topped up water level, level has been the same since.

[Cabriomin]

I had exactly the same with my MPI, changed the coolant again being a little more careful and was fine.

[Neil1275]

Hi All

 

Today have been looking at fault again and decided to recheck all the wiring as when you disconnect temp plug fan should run.

 

So started at the fuse again and worked forward, when i got to the light green/black wire which comes from the ecu to signal the relay i decided ro disconnect ecu plugs and check continuity from the pins.

 

What i found was the light green/black wire has corroded through and only held to the plug by the plastic coating.

 

Will see if i can get a new pin and refit or see if enough wire on original pin to solder a wire on.

 

How do i send a pic?