406 diesel brake and electrical cooling problem

fangio · Post by **fangio** » 20 Aug 2002, 23:06

I have a 1.9 406 turbo diesel fitted with Air Con and ABS. Presently experiencing two
unrelated problems - NEED HELP to indentity and rectify problems without a huge garage bill!!
The first problem, the cooling radiator fans are cutting in often and the STOP light on the dash is
comming on intermittently even though the water temperature is normal! The fan will often run
for sometime after the engine has been switched off. The second problem, BRAKES - an intermittent problem where you depress the brake pedal which seems 'soft' and for a split second there appears to be no braking effect. Then the pressure will return to the pedal, a sensation as though the pedal is riseing under your foot!
Any thoughts out there email andrew@aphoto.demon.co.uk

NiSk · Post by **NiSk** » 21 Aug 2002, 13:26

Well, sounds like you've either got a lying temperature gauge or a temp. switch! The fans and the stop light are connected to temp switches. The fans running on after switching off the engine is normal (as long as the engine is hot, that is) since there's no ram -air being forced through the radiator by the car's motion. You could have a problem with gunge in the rad, or a worn out thermostat. But check the temperature with a good old fashioned external thermometer in the rad-cap or expansion vessel when the fans are running after switch off to see if the temp. gauge is lying.
Do you have ABS brakes on your 406? sounds rather like it from your description. If so, does the ABS warning light on the dash light at the same time asa the funny feeling on the brake pedal?
//NiSk

fangio · Post by **fangio** » 21 Aug 2002, 21:08

Yes the car has got ABS and no the dash ABS warning light hasn't come on.
Has anyone got ideas about rectifying the brake problem which I guess is either Servo or more likely ABS related. Basically where do I being?????

NiSk · Post by **NiSk** » 22 Aug 2002, 13:04

You can start by locating all the cable junctions in the ABS-sensor wiring. They are a well-know cause of malfunction. At least pull them apart, clean them and dose with something to stop water ingress. If you really want to go to town, solder them instead. The cable from the ABS block to the ABS computer usually has a wacking great connecter (80 pin or something). Pull it out and make sure the contacts are clean. While you've got it off, check the resitance of the ABS sensors at the connector (not sure which pins they are on your car, but Haynes has a wiring diagram that shows them). The resitance should be around 1000 ohms +/- 400 if any of them are way higher or short circuit, you've found your problem.
Well, thats a start!
//NiSk