Got a temp sensor fault on my Escort GTi, when I bought the car it was constantly reading full temp, so I changed the sensor and it was fine problem solved, then about three weeks later it went dead, wont read anything at all, but I noticed that this is only when I have the engine running, when I turn the engine off, but turn the ignition on it goes straight to max temp then if i turn the engine over it drops dead again, is it the sensor thats fucked or is there soemthing else going on?

cheers.

 

Easiest way is to unplug the sender, gauge should not work, if it still reads max then theres a short in the sender wire, if it dosen't then the senders faulty, earthing the wire will also cause the gauge to read max temp as a test.

Martin

 

yeah, but thats what I dont understand, if I take the plug off, it is dead what ever (ignition on/engine off or Ignition on/engine on) which would suggest the sensor itself (even though it is only three weeks old) is buggered, yet if i plug it in, it read max under one set of circumstances and doesnt read under another, just want to be sure it is the sensor before i got and fork out for another new one.

Cheers

 

Any other possibilities

 

With the plug off you should have no reading no matter what you do as there is no ground. It sounds as if the sender is working in reverse, I.E with ignition on it has no resistance so max reading yet with the engine running its giving full resistance hence no reading on the gauge. I would think it's a dodgy sender.

Martin

 

Right up date, put a new sensor on there today and it blew up so i took the plug off but the gauge reads full?! (this is with the ignition on but engine off, iff i turn the next notch to start the engine the gauge goes dead) so i had a look in the haynes manual to look for a wire diagram, only to find it doesnt show mine in there!? I have 2 wires from my temp sender, 1 red+white and 1 black+blue, which one does what?