Coolant Light Flashing? What else Causes it?

[iceviolet 0]

As title, my coolant light started flashing a while ago now, the car was then garaged for the winter and now its time to bring it back out again. I bought a mk4 header tank and plug to go with in hope that this would cure the flashing light and also allow me to top up coolant without the use of a hammer.

 

Fitted it today and no joy, still flashing constantly.

I understand it flashed when not enough coolant is present and also when overheating. The car has plenty coolant and is not over heating.

 

So what else could make it flash?? Could one of the yellow,blue or black sensors on the thermo housing cause it??

 

Cheers

[volksworld13 0]

try disconnecting the coolant level switch in the header tank, see if the lights go out, may poss be coolant temp sensor in the housing. they arnt much to replace.

[streetpreache47 0]

I have the same problem, I thought it was the sensor so I changed the tank but the light still flashes, it goes off when I remove the header tank plug and bridge the connectors only to come on again. Would this be a plug problem?

 

Also where is the temperature sensor on a KR?

[iceviolet 0]

i have tried bridging the connection too and it made no difference, still flashing.

Its just annoying more than anything! might take the bulb out!lol!

[Yandards 0]

Check the relay at position 5 on the relay board, it controls the coolant flashing light.

[streetpreache47 0]

Relay 5 is that on the fuse board,

 

additionally what would we be checking for, is there a test to see if the relay is duff?

[davidwort 0]

Check the relay at position 5 on the relay board, it controls the coolant flashing light.

 

now you mention that!

couple of years ago I asked you about a random light flashing thing and you just went :shrug: :lol:

[Yandards 0]

Check the relay at position 5 on the relay board, it controls the coolant flashing light.

 

now you mention that!

couple of years ago I asked you about a random light flashing thing and you just went :shrug: :lol:

 

Yeah sorry, just had another one of these questions crop up on another Corrado site, took me about 40 mins to trace the wiring and cross check the relay locations though!

 

As for checking the relay, if you remove it you can check the wiring for continuity to ensure it's not a wiring snag, from socket 2 in position 5 on the relay/fuse box to the sensor at pin 2 on the plug (wiring colours vary by model and year so I am not listing it) should give you continuity (resistance check on a multimeter). From the relay plate at socket 3 you need to do the same but to the plug on the back of the instrument cluster this will either be pin 23 or pin 2 depending on when your car was built.

 

Looking at various versions of the clocks (the earlier Corrado wiring diagrams are much more detailed) the relay is on a timer, once ignition is in the run position the relay has 5 seconds where it allows current flow to ground, effectively shorting out the coolant warning circuit, to give you the 'test' warning. If the relay is broken/stuck then it remains in the initial test position providing a constant flashing light.

 

Interestingly both the coolant warning light and the coolant gauge indication are using the same signal wire (regardless of clock variations) I am guessing the voltage stabilser compensates for the voltage spike that must come from the coolant shortage indication..

 

As for a new one, part number 191 919 376 A around £20.

[davidwort 0]

great, cheers :salute:

 

this might explain why very occasionally the light goes mental and the gauge rises right to the top very quickly, then will either drop of it's own accord or resets when you turn the ignition off/on.

from what I understand if it was the voltage regulator then other instruments would be affected, and I've changed/checked just about everything else apart from the actual gauge unit.

[Yandards 0]

great, cheers :salute:

 

this might explain why very occasionally the light goes mental and the gauge rises right to the top very quickly, then will either drop of it's own accord or resets when you turn the ignition off/on.

from what I understand if it was the voltage regulator then other instruments would be affected, and I've changed/checked just about everything else apart from the actual gauge unit.

 

Yeah the voltage regulator is just a 'damper' and if it was blown/faulty your fuel gauge would go nuts too.

 

To be honest it's a bloody stupid system, why the coolant warning lights needs to be wired into the same cable as the signal from the coolant temp sender just seems like trouble to me.

 

Oh well should be a cheap fix for folks and it's an easy one too..

[streetpreache47 0]

Yan you are a star!

 

I think we have a winner on the relay, I removed then reseated it and it appears to have cured, will monitor then con check if the problem re-appears.

 

I did notice that sometimes my wipers/heater haven't worked but tap the fusebox area and it works, I may have a loose connection at this end!

 

Thanks again

 

Anthony

[Yandards 0]

Yan you are a star!

 

I think we have a winner on the relay, I removed then reseated it and it appears to have cured, will monitor then con check if the problem re-appears.

 

I did notice that sometimes my wipers/heater haven't worked but tap the fusebox area and it works, I may have a loose connection at this end!

 

Thanks again

 

Anthony

 

That's more likely to be the X contact relief relay sticking.

 

It's in position 4 on the relay board and IIRC unloads all the heavy consumers (like heaters and wipers) when the car is starting.

[iceviolet 0]

Check the relay at position 5 on the relay board, it controls the coolant flashing light.

 

I would if there was a relay in position 5!! its not got a relay in! Im guessing i should have a relay in that slot??

How the hell has it worked before if there was never a relay in there??

Im confused :scratch: :scratch:

[Yandards 0]

Regardless of model you should have a relay in position 5.

 

If you have not got one then it should be the one with number 42 on the back of it and correspond to the part number listed above.

 

Not wishing to teach you to suck eggs but you are aware that it is a 12 socket relay board ?

[iceviolet 0]

Yep deffo not one in location 5, it has a 5 on the plastic on the middle of the socket. The one next to it, 6 is the flasher relay which i have replaced before. Never had one in 5.

I just cant see how it worked before without it??

 

Im going to vw tomorrow to pick up some bits, guess ill have to buy a relay aswell. Most likely be to order so will have to wait to see if it cures it!

[iceviolet 0]

Just consulted the bently manual, and it states that from 1992 to Jan 1993 relay 5 was open, then from Jan 1993 onwards relay 5 had the ECL Control module, production number 43 as yandards stated before.

My car is an L reg, first registered on 12/10/1993 according to the log book. So i would of thought it would be Jan 1993 onwards?? with the relay number 5??

Or is this a load of garbage as the bentley is for the american corrado??

[Yandards 0]

American spec relay panel, try this one for UK/Euro models..

[CazzaVR 0]

Thanks for the info, Yan. Mine flashes on start up as normal, goes out, then starts flashing again and stays on unless you turn off the ignition and strart her up again. It stays off after that. Checked, and mine doesn't have a relay in slot 5 :? I'm assuming it hasn't had one for a while (before I bought the car), but why wasn't it flashing for the first few months of my ownership? Only started flashing after I replaced the rad/flushed & replaced coolant :?

[Yandards 0]

Thanks for the info, Yan. Mine flashes on start up as normal, goes out, then starts flashing again and stays on unless you turn off the ignition and strart her up again. It stays off after that. Checked, and mine doesn't have a relay in slot 5 :? I'm assuming it hasn't had one for a while (before I bought the car), but why wasn't it flashing for the first few months of my ownership? Only started flashing after I replaced the rad/flushed & replaced coolant :?

 

Sticky coolant switch?

 

I still don't really know how the set-up works, the relay may only serve the purpose of providing the start-up flash..

 

I suspect your coolant flush is the reason yours was on the fritz, the in reservoir units are not the best. Interesting that so many cars seem to be missing this relay but it is shown fitted to the later models in the wiring diagram.

[Jon_vr6 1]

Just checked my fuesbox to see what relays i have and theres not one in number 5 slot, I DONT have the coolant light flashing problem so if you dont have one in slot 5 that cant be your problem

[iceviolet 0]

Thats what i thought, because it did work before so why would it suddenly require a relay that wasnt there in the first place. I guess that it just depends on how early or late your car is

[D-REG GOLF G60 0]

hi i av this problem 2 ,ive dun a g60 conversion 2 my golf,the light wasnt flashin on the golf i took the engine out,bt it is now,and i ent got a relay in slot number 5.

[Yandards 0]

Just checked my fuesbox to see what relays i have and theres not one in number 5 slot, I DONT have the coolant light flashing problem so if you dont have one in slot 5 that cant be your problem

 

All I can say is that given the VW electrical diagrams for a European Corrado every model year up to the last one built shows a relay at position 5 on the relay board for the coolant warning indicator lamp. If folks don't have one and your coolant shortage light is flashing for a few seconds at startup then I don't know how it's working.

 

The other option is the wiring diagram is incorrect and earlier models (no idea when though) need the relay and later ones don't. Need to survey a few cars this year and see if I can work out what it going on.

[Jon_vr6 1]

Yep mine flashes couple of times at IGN position 1 then goes out weird that the wiring diagram says it has one though

[iceviolet 0]

It is a bit baffling how some work with and some without, i went to the scrappies the other day, a late corrado in there didnt have a relay 5 in the fusebox either.

Could there be some kind of relay/chip on the actual clock circuit board that controls it. As ive been looking at the wiring diagrams,and i am no expert with electronics but all i see is that from the coolant level sensor in the expansion tank, one wire grounds in the headlight loom and the other goes to the dash.

Thinking about trying someother clocks??