[trebor]

Originally Posted by Bartje

On my 2003 ZT-T Diesel the FBH used to work perfectly, but this winter it somehow stopped working completely.
When activated (by the timer or remote) Nothing happens, not even a click or anything.

By switching it manually (pin 3 to ground) the same... nothing..

According to the schematics, there's 12V and ground at the 2-pin connector, and there's 12V on Pin 1 (If i'm not mistaking, haven't got the schematics at hand).

But... nothing happens... all fuses are (obviously) ok..

So.. PCB dead ? or could something else be a problem?

First of all take a look at this and decide if you have the early or late model FBH https://www.the75andztclub.co.uk/for...d.php?t=310873

The 98570B takes 12 v to pin 1 and earth to pin 3

The 66232C takes 12v to both pins 1 & 3

Once you know which one you have you will know whether the test you ran by putting earth to pin 3 was a valid one, if you have the 66232C you can now try 12v to pin 1

If you have a remote I would expect both pins 1 and 3 to be populated in the 6 pin plug

Just to eliminate any issue with your remote set up, start the car when temp is 5 degrees or below and see if the heater works in supplementary mode

If after trying the above your fuses are ok and you have 12v and earth to the 2 pin plug and the heater is still completely dead than your PCB needs to be fixed or replaced