Fan not cutting in...

[Daz155HGT]

I noticed yesterday that my fan is not coming on when the engine gets hot.

Not sure how long its being doing it, i have a funny feeling this relates back to the problem i thought i had with the fuel cut-off switch.

When driving the car (i drive mostly motorway), the temp gauge gets to half way (as it always has), and the car drives fine.

But if i park the car after a journey and try and start it before the engine cools down, it will not start...

I haven't noticed it before as i drive to work in the morning and don't use the car until i am ready to come home.

But tested the theory twice yesterday and the car will not restart until the temp gauge gets down to roughly the last mark (before cold)

Checked the fuses, they are ok, so just wondered if anyone has come across this before?

I seemed funny to me that the car won't start, i would have expected it to just get hotter and hotter...lol

Daz

 

[Anonymous]

Did U try if the fan works ?
Bringing the car to the point where the fan should kick in.

If the fan isnt working, its prob. the thermostatic switch or the fan motor.
The fan motor can be tested if U remove the connector to it and connect it directly to the batt. whit some wires.

The fuel cut off switch activates its self over 25 km/h and it cuts off the fuel pump.
So it can be something wrong whit the fuel pump / cut off switch wires / contacts.

sven

 

[Anonymous]

Yeah, both times yesterday the car was red hot and the fan didn't kick in...

I will be testing the fan this morning, but i can virtually guarantee the fan will be fine...lol (don't ask me why i know, i just know )

I really don't think its a problem with the fuel/cut off etc...

During one of the tests yesterday, i didnt even move the car, just started it up and let it get warm, turned the engine off, wait 5 mins and it doesn't start.

I have a funny fealing its going to be the thermostatic switch...is that the same as the thermostat? do you know where it is located?

Thanks for the help/advice

Daz

 

[Anonymous]

That is the only thing on the radiator whit a connector on it.
It measures the temp. of the cooling water, and when it gets over 85 - 90°C (not exact) it starts the fan.
It looks like a plug whit a connector on it, costs about £5-10 in my country and its easy to change, + it a common prob. on italian cars.
To take it off, U have to unscrew it, screw in the new one and fill the cooling system again.

Sven

 

[Tom]

I have a feeling the ECU controls the fan, could be your engine temp sender is dodgey.

The parts catalogue shows no switch for the Mk2.

 

[Anonymous]

I dont see it either (just found out the site is back). But still look if U have it.

So Tom U think its the ECU that controls the fan ?
But how does it measure the water temp - the head temp is different from the water temp ?

sven

 

[Tom]

It measures the water temp in the head.

 

[Anonymous]

Right then...

There is nothing at all connected to the rad (except the pipes of course)

Fan works fine when connected directly to the battery...

So...can anyone tell me what these two relays are for?

Under the cover next to the battery...

These two... (red and black - the same size ones)

This is whats on the cover...bit strange as there are 7 symbols, but only 4 relays...lol

The reason i ask is, if i remove the red relay, the fan kicks in...

Daz

 

[Anonymous]

Relays for the batt. (sorry Daz dont know the correct positions)

Slow rpm of the fan
Time interval sender for high rpm of the fan
High rpm of the fan
Air Con compressor
Relay for switching the fuel cut off
Relay for the fan (only 1.8 engine)

so its prob. that 1 relay is not working right.

sven

 

[Anonymous]

Just to add: its from my handbook.
By the look of the symbols on your pic., I can tell only this:
1 - fuel cut off
2 - fuel pump or something
3 - ABS / brakes
4 - Lights, I think the long ones (inner side of the head light)
5 - automatic transmition
6, 7 - can make out what they represent

sven

 

[Anonymous]

Thanks for the info Sven...helpful as always...

Don't know when they mean, but the last but one looks like a fan inside a tank. The last one looks like a snowflake inside a circle...

Daz

 

[Tom]

4 is the lamp washers.

Having seen the wiring diagrams Fiat have I wouldn't bother asking them

 

[Tom]

Daz, those will be cooling fan and aircon.

 

[Anonymous]

Thanks aswell Tom...

But...does anyone know what the red one is?

Daz

 

[Tom]

Probably the fan relay

 

[Anonymous]

hmmm...lol

But why would the fan kick in with the relay removed?

I have noticed the fan kicks in wether its hot or cold...

I guess i am safe to remove the relay and still drive the car?

Daz

 

[Tom]

not got a wiring diagram so who knows...

Bloody fiat, bloody haynes...

 

[Anonymous]

Got a haynes, but its a HGT, which (as my luck goes) not in there...lol

Looked at the wiring diagrams for the other engines but can't see anything of relevance

Oh well, i guess i will have to remove it and find out...

I'm guessing that even though the fan is kicking in, as soon as the ignition is off the fan is going to stop...which will leave me with the same problem.

I have a temp controlled relay which i have bought for my amp, but the max setting is 30 deg C, which i though about installing, but wondered about how long the engine would take to get back down to 30 deg...would this drain my battery too much...?

Suck it and see i guess...lol

Daz

 

[Tom]

You want to maintain the engine at about 85-90deg.

The haynes mentions that later cars don't have a rad switch but the wiring diagram only shows the early version.

Has to be said, its one of the least helpful of all the haynes I've got. The older ones (MGs, mini etc..) have pages and pages of wiring diagrams for every year/model/variant you can think of.

 

[Wimmy]

Mine doesnt work kick in either.

I have checked the fan which works, the relay also works after swapping over with a 1.2.

The temp sensor seems the only thing that could now have gone which is located right at the back of the engine which seems a pain in the ass to get to.

I'm thinking of wiring a direct switch to the fan to keep the sod cool when in standing traffic