Peugeot 306 diesel red stop light is on and both fans run

It is also possible you have other issues, such as a bad thermostat, bad temp gauge sender, missing fan shroud, bad fan thermostat switch, bad fan motor, or even just clogged radiator core or fins.

use a diagnostic to detect the fault code

firstly you need to check the coolant level and make sure there are no air bubbles in the cooling circuit
secondly the thermostat could be damaged and stays in the closed position
thirdly the cooling radiator could be clogged and it must be flushed or replaced
you have to take into accont that it could be a faulty message sent by faulty temperature sensor or bad connector of the senser
so you need to open the hood and decide, is the engine very hot or is it normal but still the fan is on

SOUND LIKE ENGINE OVERHEATING,CHECK COOLANT LEVEL MAKE SURE YOUR RADIATOR FULL OF ANTIFREEZE.IF YOUR COOLANT OVERFLOW JUG IS EMPTY COOLANT LEVEL IS LOW.NEED ADD MORE COOLANT TO OVERFLOW UNTIL COOLANT STAY AT FULL COLD MARK. DONT OVER FILL COOLANT OVER FLOW JUG.IF COOLANT OKAY ENGINE OVERHEATING REPLACE THERMOSTAT.MAKE SURE ENGINE COOLING FAN IS WORKING IF YOU COME TO A STOP CAR SITS FOR A LITTLE WHILE START OVERHEATING THE COOLING FAN NOT TURNING ON , BECAUSE COOLANT FAN FUSE BLOWED OR YOU HAVE BAD RELAY,THE ENGINE COOLANT TEMPERATURE SENSOR FAULTY.IF YOU HAVE THE CLUTCH TYPE COOLING FAN, MAKE SURE WHEN TURNING CLUTCH FAN WITH HAND COOLING FAN SHOULD HAVE RESISTANCE WHEN HOT.IF CLUTCH FAN FEEL WOBBLY AND LOOSE REPLACE IT.TAKE VECHICLE TO AUTO ZONE OR ADVANCE AUTO PARTS OR ANY AUTO PARTS STORES THEY WILL CODE SCAN CAR FREE AND GIVE YOU THE CHECK ENGINE LIGHT TROUBLE CODE TO SEE WHAT CAUSING CHECK ENGINE LIGHT TO TURN ON.

i have vauxhall vivaro van got starting problems could be glow plugs but now i have a flashing stop light on what looks like a picture of a engine

renew the whole unit ,the resistor in the motor unit is finished ,the thin wire is controling the feed into the motor via a earth resistance in the ballast resistor ,hence variable speed .But you should have a 12v supply via the red cable if you havent then thats your problem ,a loose connector ?? fuse ,fuse holder, broken wire

check your glow plugs they may be damaged or dirty

what year is the car pet or diesel

what do you mean by stop light coming on is it the large red STOP on instrument panel coming on if so check water level in radiator,also check your engine oil level

how hard was your car hit?? is it petrol or diesel? if its petrol the first thing that pops to mind is that, under the bonnet near the back (cant remember what side) you'll see a big red button, press it and try agaijn.. this is a knock sensor for if you ever have a crash... ive set one off just by parking and bumpin the car in front