Coolant light not working

[oddnumber]

Morning all, got a problem as per the title. When the ignition is on, the red coolant light doesn't do it's flashing routine. I initially suspected a dodgy LED but noticed that when the hazards are switched on, the coolant light flashes!

So, I'm thinking a bad earth somewhere. Where is the coolant light earthed? Any ideas or suggestions much appreciated.

[MidLifeCrisis]

Try cleaning up the ground crowns next to the fuses.

[oddnumber]

Thank you very much for the reply, will give it a go and see what happens. Would a dodgy earth give similar symptoms (ie one circuit affecting another)?

[MidLifeCrisis]

Yep - strange things happen when an earth disappears.
It's possible that activating the hazards is providing a ground path for the coolant flasher ...... (the circuits are connected in that the ground for the coolant flasher is linked to the ground for the hazard switch indicator light)

[oddnumber]

Awesome, thank you - will get my toothbrush and wd40 out later

Will let you know how it goes, too...

[oddnumber]

Right, I've cleaned everything and checked the crowns and everything looks clean and connected. I had to fit another spade connector but even that wasn't too bad. The bloody thing still doesn't come on

Is there anything else that could affect the functionality of that light? I've read of a relay (no.43?) but mine has the older relay layout and doesn't appear to have one.

Any advice would be grand. I might be being picky but I'd rather know how much coolant I have

[MidLifeCrisis]

Does the High Beam blue light on the dash work?
Does your coolant temperature gauge work (i.e. the needle)
Does the fuel gauge work?

All three of these items use the same ground line out from the gauges - so if all three of these work OK then the problem might be somewhere else.

That relay 43 that you are talking about is actually a little circuit board housed in a relay sized box - however I doubt that this is the problem as the coolant light should flash when you first turn the ignition regardless of whether this relay works or not (for example you can take the relay out and the coolant light should still flash when the ignition is turned).

If turning the hazards on does make the coolant light flash - then I would suggest that there is still a grounding problem - the problem may be within the plastic PCB in the gauge itself (i.e. a broken track somewhere).

Let us know if the High Beam, Temp Gauge and Fuel Gauge work?

[oddnumber]

Morning!

OK - the temperature gauge and the fuel gauge both work (not too accurately I fear). Th high beam dash light and coolant level don't.

[MidLifeCrisis]

That does sound like the earth to dash gauges is missing/broken etc.
Do the gauge lights work (the ones that light the gauges when the headlights are on)?

Do you have a multimeter so that you can check the ground pin on the long white connector on the back of the gauge pod. Yank the cover off the gauge pod, disconnect the connector and check to see if pin 5 has a good connection to ground?

How are the temp/fuel gauges misbehaving? You will prob find that fixing the earth issue also fixes these gauges too - double win!!

[oddnumber]

aahhhh this is getting interesting - you're right, the gauge lights dont work. The previous owner fitted some aftermarket led ones that work by switch.

I don't have a multimeter, sure I can find one though. Could it simply be a case of running a wire from pin 5 to a new earthing point?

I think the temperature gauge is reading a little low (could be another matter though ) and the fuel gauge swings erratically about within the range of 1/4 tank.


Thanks so much for your help and time, it really is appreciated

[MidLifeCrisis]

I don't have a multimeter, sure I can find one though. Could it simply be a case of running a wire from pin 5 to a new earthing point?

Yep - certainly try that as a bit of a test to see what it does.
The break could be within the plastic printed-circuit-board thing in the gauge pod but grounding pin 5 would be a good simple test to see if that fixes it.

Also you could ground the coolant gauge pin directly - it's this one (circled in red);

[oddnumber]

I don't have a multimeter, sure I can find one though. Could it simply be a case of running a wire from pin 5 to a new earthing point?

Yep - certainly try that as a bit of a test to see what it does.
The break could be within the plastic printed-circuit-board thing in the gauge pod but grounding pin 5 would be a good simple test to see if that fixes it.

Also you could ground the coolant gauge pin directly - it's this one (circled in red);

Woohoo fantastic, makes sense now! If grounding the gauge pin directly fixes the issue, is it 'right' to leave it like that? Are replacement PCBs available?

Thanks again, I think we're getting somewhere here. It's a shame I have to wait 'til tomorrow to try it!

[MidLifeCrisis]

They'd be no problem with leaving the additional ground on that pin but it might be nice to know where the problem is so that you can ensure that the other items in the gauge pod are also getting a good ground.
i.e. high beam light, temp gauge, fuel gauge, gauge lights, clock (if fitted) and the ground also passes out to the Hazard Warning Light switch

[oddnumber]

OK excellent, will give it a go.

Can you get replacement PCBs?

[MidLifeCrisis]

I don't think you can get replacement PCBs new - you could try asking in the 'Wanted' section but chances are it'll be about as hosed as yours 'may' be.
Another option is to hardwire the dash - have a look in the Wiki for details (that's the route I intend going down)