Water temp warning light

Has anyone experienced the temp warning light(2nd bottom right - warning light cluster) coming on? I have owned the car (Turbo)for 13 years and never seen it come on until recently.
It has recently started to come on only when the engine has competely warmed up, even though the temp gauge is showing normal and the coolant level is OK. Furthermore, neither the rad fans or the engine bay fans are operating when the light is on indicating that it is not excessivly hot? The fan belt is also OK

Any advise would be appreciated as I would like to resolve the issue rather than ignore it, especially as one day I am sure that it could be the one light that could save me cooking the engine !!
I have looked at the wiring diagram, but am unable to determine if the light is activated by the same sensor that feeds the temp gauge?

Help please, before I start pulling everything apart.

Thanks,

Jeff

Jersy Jon will be along soon to explain the wiring diagram to you, and us all.
Worth his weight in Gold !

Mine came on )or at least it glowed faintly) when I first bought the car. Turned out that the engine cooling fan had failed, consequently the temp in the engine bay reached 90+ when stationary.
Replaced the cooling fan and it has come back on since.

If your fans are working then my money is on the sensor itself being suspect.
Perhaps with age it's switching on at a lower temperature than 110 degrees (I think that's the switching temp).

God I wish I could spell correctly. Ignore that last post....



Mine came on (or at least it glowed faintly) when I first bought the car. Turned out that the engine cooling fan had failed, consequently the temp in the engine bay reached 90+ when stationary.
Replaced the cooling fan and it has not come back on since.

If your fans are working then my money is on the sensor itself being suspect.
Perhaps with age it's switching on at a lower temperature than 110 degrees (I think that's the switching temp).

[mettersl]

Are you sure its a water light, not the engine bay hot light? This is the LOWER of the two thermostats near the Turbo and should be a 110 or 120 degrees 'stat. It is triggered at higher temperatures thn the fans so check the fans are working as a first step.
The fans on a GTA have a complicated regime for turning them on depending on age (John C can explain). The upper thermostat (90 degree) is the one that puts the fans on, or on fast depending on model. Unfortunately garages often fit them the wrong way around as that is what the parts book (but not workshop manual) says.
So check that both fans are working and if not try shorting out the upper thermostat and see if they come on. There are relays involved in this and on some models an oil temperature sensor too, so there are plenty of opportunities for faults.
Of course the front fans need to be working too.
Good luck

Lee

Has anyone experienced the temp warning light(2nd bottom right - warning light cluster) coming on? I have owned the car (Turbo)for 13 years and never seen it come on until recently.
It has recently started to come on only when the engine has competely warmed up, even though the temp gauge is showing normal and the coolant level is OK. Furthermore, neither the rad fans or the engine bay fans are operating when the light is on indicating that it is not excessivly hot? The fan belt is also OK

Any advise would be appreciated as I would like to resolve the issue rather than ignore it, especially as one day I am sure that it could be the one light that could save me cooking the engine !!
I have looked at the wiring diagram, but am unable to determine if the light is activated by the same sensor that feeds the temp gauge?

Help please, before I start pulling everything apart.

Thanks,

Jeff

maybe joining the club might help solve the problem eh

Thanks for the responses. Maybe I didn't explain the problem clear enough in my original message.

The warning light that is coming on is the water temp warning light (warning cluster lights, bottom row 2nd from the right) and not the engine bay overtemp light which is the centre light on the upper cluster. I have already shorted out the engine bay fan switches to make sure and the fans both came on and the correct light came on....so it doesn't seem to be that.

I have looked at the wiring diagram again and I think that it is probably the water temp sender (thermistor) that is giving the problem. The sender is positioned behind the thermostat and has a 2 wire take off, which I assume feeds both the gauge and the light - one for each.
What I don't know is if it is possible for the resistance to deteriorate with age and cause the light to come on at a lower temp? Either that or the gauge is under reading - which one is correct?
I am favouring the light is coming on prematurely because the Rad fans are working OK and there is no noticeable overheat of the engine.
I think that the wiring and circuitry is OK, because it is only coming on when the engine gets up to running temp, when the engine is cooler the light is not on or goes off when it cools down,

I suppose the only option is to replace the sender and see if it corrects itself ? I phoned Renault for a price which wasn't too bad for the stealers at £27, but the twist is that they have modified the sender and you need to purchase a new lead at £36 to be able to connect it?

If anyone has a sender that they do not need with the old plug fitting please let me know and I will gladly take it off your hands.

I am going to check all the connections again to see if it changes things , I will let you know how I get on.
Thanks,
Jeff

I cant spell and I cant read the posts correctly... I'll need shooting!


It may be worth checking the tension on your alternator /water pump drive belt. This can slip slightly and without a noise you'd never know - apart from the warning light that is.

Had this happen to me on a non GTA, I cant recall if the rad fan came on or not.

If there are two sensors; and I believe there are. One for the temp warning light and one for the rad fan (which I think is located on the rad itself) , then you could get an overheat warning without the fan coming on.

Problem Solved!!

I removed the connector block from the sender and checked the terminals with a tester. I found that one had a resistance present and the other was on open circuit. I presumed that the contact with the resitance was the feed to the gauge and the open circuit was the switch for the light.

This was confirmed when I warmed the engine up and checked the switch contact which showed that it had closed putting the light on. The temp at the time was showing only 90 on the gauge which should be too low to put the light on?
I assumed that the sender is faulty and the only way to check was to replace it.

I phoned my local motor factor and was surprised after I had provided him the Renault P/No 77 00 778 782 that he said that he had one in stock.

After a bit of a struggle to remove the old one ( interconnector hose and top hose removed), I managed to remove it. After fitting the new one, topping up the coolant and taking it for a spin to get it up to temp, I was very pleased to find that the light did not come on.

If anyone has the misfortune to have the same problem, then try your local motor factor first.
The sender part no is : Interconnector No 53284 and only cost £15 inc vat. Better still it is a direct replacement for the original Renault P/No 77 00 778 782 which Renault said was no longer available would cost £27 plus vat and does not need the new lead that Renault said would be necessary for another £37 plus vat.
All in all a considerable saving and much easier to fit than having to remove/replace the connector lead.

Thanks for all your replies

Good to see that you have taking the time, and effort, to post your findings for the benifit of all the other members. Your savings will now allow you to join the club for what seems like 'free', woth it's weight in Gold.

Good to see that you have taking the time, and effort, to post your findings for the benifit of all the other members. Your savings will now allow you to join the club for what seems like 'free', woth it's weight in Gold.

it will be when he needs a £90 track rod end for his steering when it fails its MOT on it...... they'll be half that price through the club....