Radiator fan not coming on

[andy c]

It works with outside power so not fan problem.
Doesnt kick in for some reason.
Maybe relay,maybe sender?Do they work off the temp sender because temp reading on dash works fine.

Any way of checking without taking to dealer?

[stevieturbo]

Once again a question with little information.

What car ??

And blatantly obvious thing to check would be fuses, then possibly relay.

And no, the gauge sensor doesnt control it. That is for the gauge.

But without knowing what car, we can have no idea what might be controlling it.

Normally its ecu controlled though

[andy c]

Its a 1993 Jaguar ,fuses are fine,Fan works.I swapped 2 identicle relays around and still have problem .I checked the loom connectors and they are all fine.Problem started when I took radiator off to put a new mount on.Put it back together filled with coolant and bled the system.It was working before and has been run up to temp twice over winter. It took a bit to bleed it.Could I have damaged the sender through localised over heating during the bleeding process?

[stevieturbo]

So is there power at the wires to the fan ?

Is there power at the fuse ?

Is power getting to the relay ?

Does the relay receive an earth trigger ?

All basic checks.

Is the engine even warm enough to require the fan to operate ?

[DaveL485]

Bridge the fan switch in the Rad.

[andy c]

Definately power reaches the fans when it is sent it.
Engine definately gets hot enough.Should come on at 88 and engine reaches 100 before I turn it off.
I will change the sender today and check the old one in boiling water.
Then try the above.

I know what a Water temp sender is, but is it the Water temp Gauge transducer as labeled on the wiring diagram?
What is the Water temperature thermistor?The feed to this has a comment on the diagram, ECU feed + 5 volts.
I have a feeling one feeds the temp gauge and the other to the ecu.
I think the Temp sender would just do the temp gauge,or am I wrong?

Edited by andy c on Tuesday 16th March 10:09

[stevieturbo]

Take it to a mechanic.

[andy c]

Nearest and only mechanic capable is 200 miles away.

[andy c]

Sorted it.
Started car from cold to have another go.little low on coolant so filled it again[doesnt have a header tank so just fill it to to.I burped a little bit more air out of the system and hey presto.I gave all the pipes ,rad etc a good dull thump and thats it.Thank god for that.
I just hope it is not an loose or dirty electrial connector somewhere and the problem becomes intermittant.

[stevieturbo]

I know mechanics are hard to find at times....but are you on the North Pole or something ?

200 miles is a little extreme for what is an easy problem

[Steve_D]

andy c said:

Nearest and only mechanic capable is 200 miles away.

I would class myself as more than a mechanic and much closer to Surrey than 200miles.

Steve