coolant flashing light

[Holty]

Hi All,

I have been trying to sort the flashing coolant light for the last week or so.

I have found a wiring issue with the level sensor, plug and cables had corroded.

I have removed the relay 43, which am I right in thinking this should rule this part of the circuit out?

The temp gague works as I would expect it to, the needle goes to 12 O'clock when upto temp and only moves a small amount in each direction.

On the back of the temp gauge I am getting 10v across the supply and centre pin, when I short the signal pin to the centre pin the needle goes from Left to right all the way.

My question is: Is there some parts in the gauge itself that could be causing me a problem?

Thanks in advance.

Ian

[Mocki]

I think you are overthinking it ....

If the gauge is working , then your issue with the red flashing light is either the relay , or the wiring to the low coolant sender

I’m sure you are aware The flashing red light in the temp gauge has two functions ....
1. If the gauge is above 3/4 and it's flashing it means over heating
2. If the gauge is below 3/4 and it's flashing , it means low coolant in the header tank.

If it's say low coolant , and you can see the header tank is full to the brim ( not the number plate flap top up tank) then it's an electrical issue , and simple fault diagnostics will need to be employed !

Unplug the wire from the sender in the top of the header tank, and use a paper clip or piece of wire to join the two pins together, this should make the flashing light go off when you run the ignition on , after it's self test .
If it does, the sender is faulty or dirty , if it stays flashing , there is a wiring or relay issue .
The Red flashing coolant light self tests when you switch the ignition on and then goes off ......

Basically the low coolant relay 43 puts a fast pulse on the gauge feed giving the over heat signal, but pulsing faster than the gauge can react to , so only the red ligh5 flashes, telling you low cooolant

[Holty]

Thanks for the reply Mocki,

Would removing the relay 43 remove any fault on the level side of the system?

If so that would half the circuit I need to look at?

[Mocki]

What is the light doing , and when ?
I assumed it was flashing when you were not over heating nor having low coolant ?

[AngeloEvs]

Removing the module 43 (or earlier 42) will isolate the level sender from the circuit. If the coolant led continues to flash with the temp gauge indicating normal then it could well be the temperature gauge needs checking. The small centre nut of the gauge provides the earth connection for the internal circuit and can sometimes become loose. There is a capacitor in the temperature gauge and this can fail causing the led to continually flash.

You have checked the voltage from the regulator and that seems OK. It may be necessary to remove the dash pod and test the gauge on a bench by connecting the centre pin to negative and the pin that normally goes to the regulator to +12v. The led should flash for a few seconds then go out - if it carries on then I suspect a failed capacitor.

[Holty]

It flashes as soon as you turn the ignition on and doesn't stop.

I think the gauge is about right as the fan comes on when the needle goes just past 12 o'clock and the fan stops when the needle is just to the left of it.

If that's where it is ment to be?

I will double check the nuts are tight.

I ran an earth cable to the centre pin just to check but it made no difference.

I may have to remove it as you say.

Thanks both for your responses

[MidLifeCrisis]

Worth having a look at the below post - it looks a lot like the capacitor on your gauge may be dead;

https://forum.club8090.co.uk/viewtopic. ... 9&t=165992