Quote Yorkie72 Out of interest, I also have a Rover 75 with a Webasto unit and that was very easy to install a switch in the cabin to operate the unit whenever I choose. (simply needs a -ve supply to the diagnostic pin

that would be very handy, as already said 5 degrees is to low, oh for a simple drawing for simple mind???

 

Hi Howard,

Yes, I'm slowly getting there with it. The 1533 timer has been delivered, I just need to run the cabling from the heater to the timer which I'm planning to fit in the center console under the armrest for now. When I've tested that, I'll add two relays to control the aux pump. I'm going to aim to fit these behind the climate control panel, splicing in between the ACCM and the aux pump relay. This will avoid having to run any additional cabling into the engine bay.

I'll keep the thread updated as I go.

Cheers,
Toby

The S-type is fitted with a different heater to the Rover 75 and requires W-bus commands to be sent to the unit periodically to keep it running. Webasto's 1533 timer will do this and has a button to start the heater without using the timer functionality which is what I intend to do.

A pin and cabling needs to be fitted to one of the heater connectors, which is run back to the timer in the cabin. The timer will also require 12V and ground to function.

 

Here's the relay arrangement I'm planning to use.