I have a 1988 z31 manual turbo uk spec. I put my heaters on yesterday and they cut out and then came back on and they were surging if that makes sense. it seemed like a bad earth so I pulled the plugs cleaned them and also cleaned the plug on the blower motor. I still have this problem. when it cuts out I have to slide the **** to 'off' and then back across to high and they will come back on.

im assuming the heater control panel/box is knackered can anyone confirm this?

thanks.

 

I would suspect vacuum leaks first.

 

thanks for the reply.

so is it all vacuum controlled? I see the multi plug on the back of the heater control panel and assumed it would operate the fan blower speed by adjusting the voltage? where will I find the vacuum pipes, will the be under the dash or under the hood?

thanks.

 

The blower motor speed is electronically controlled, but all the flaps are vacuum operated.

The lone vacuum line originates at the vacuum pump/tank at the front right of the car. At least, I believe it will still be front right even for you over there...