Heated Drivers seat wont shut off

[stocktake]

As the switching is all on the negative side you should also see if the seat still heats with the switch removed, this would indicate a short to ground on the wiring after the heater element.

[alanaslan]

Originally Posted by SD1too

According to MG Rover’s wiring diagram, there aren’t any relays in the circuit Alan. I agree with your suggestion to check the switch.



Simon

When I think back on the last 75 seat squab heater I replaced I have to agree there wasn’t one, just a very chunky fuse. I have memories of replacing the drivers seat heater Squab with an aftermarket carbon fibre one and having problems as the timer switch operates on the negative pole. So rather than switching the power on to the squab you have a permanently powered squab and the switch only completes the circuit back to one of the vehicle earthing points. I think it may have been the one under the steering wheel on the offside bulkhead. Please someone correct me on this as it was a long time ago. I seem to remember this earth point having lots of wires connected to it.
I have a recollection of one car where the wires going to this earth point or negative point having got very hot due to a circuit overload and all the wires having lost their insulation and having become a molten burnt mass of wires. I am sorry I can’t remember what had caused this fault but remember having to run new cables of the correct size both to this earth point and the one in the middle door pillar.
Sorry I realise this will just mean more time spent with the multi meter to find a problem that might not be there
Kind regards
Alan


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