'Stop Light' flashing - only if aircon on?

[neil123]

Mysterious, to me anyway!

Heater fan working ok, aircon working ok as far as I can see.

STOP flashes after a while if aircon (or demist, which obv switches on aircon regardless) is on. Goes off it AC switch turned off and 'demist' deselected.

Comes back on (no0t instantaneously, but after a few seconds) if AC switched back on.

Any clues chaps? (Other than don't use AC - I've considered that one!)

Thanks

Neil

[GiveMeABreak]

Car model, engine, year???? Crystal ball's run out of crystals this week. Even better a VIN.

[Stickyfinger]

Don't think 2cv's had AirCon

[GiveMeABreak]

Don't think 2cv's had AirCon

No just unzip the roof and flap the windows out!

Re the issue: I'm not one for jumping in without this basic info - BUT, I suspect the Stop light is coming on because the engine cooling fan is not kicking in - which it should do with the Air Con switched on to dissipate the additional heat generated from the condenser radiator.

Possible things to check are the engine fan fuse, the contacts and wires around the fan electrics (commonly water can corrode these) or the fan could be seized / over tightened, causing the fuse to blow. The fan motor itself could be knackered too of course - but check these other things first.

[Hell Razor5543]

I would take a look to see if the cooling fans are running. If they are not, that could cause the flashing lights.

[harryp]

Have had this problem several times. Many posts about it. Check the relays in the triangular housing between the rad fans. IIRC it's the centre one that causes problems and usually because the relay base and pins are corroded. Almost impossible to get at from behind and wiring is very tight. Suggest you remove relay, clean terminals and do what you can to do same on base. Lots of contact spray and refit. If iit goes again/is intermittent, try turning the relay & base 180 . Well my base came loose and will not go quietl9y back and is works ok like that - due I imagine to the pressure maintaining enough electrical contact. Sounds bizarre I know, but it works for me.
Now ducks down for the purist onslaught .
If anyone has a sure way to remove/replace base I really would like to know; as long as it doesn't start "remove car from relay"

[neil123]

Thanks chaps - been away for a few days, will get on this and report back.

Cheers

Neil

[neil123]

Car model, engine, year???? Crystal ball's run out of crystals this week. Even better a VIN.

My Cars: 2001 Xantia 110 Hdi Forte estate !

[c.morewood]

Neil, check the fans will turn with the engine off. One of my fans will occasionally stick on its surround giving the same symptoms

[evilclive]

One of my fan motors had died, which gave exactly those symptoms. I replaced it with a spare, and the light kept flashing, which was somewhat disappointing - but a couple of days later it stopped and I can now see the fans spinning if the AC is on.