Heated seats not functioning. Switches?

YMGF · 11th April 2022, 14:31

Can you give me your thoughts please on my non-functioning heated seats. I expected to find either broken elements or thermostats. However, in both cases, I have 12V on the yellow wire at the switch, indicating that all is well with the seat and wiring before that point.
I have checked the black wire on the switch for grounding, which it has. Both switches illuminate when seats switched on.
Could it be failures on both switches? It seems unlikely but that's what it's pointing to.
Unless I missing something staring me in the face, which is also possible.
Thanks,
Michael

stocktake · 11th April 2022, 15:08

Been an awful long time since I did any work on mine but seem to remember the switching on these is on the neg side so you could show 12v right through. Not known switches to fail but the same cannot be said for the under seat connections. Worth remembering the switches do have a timer on them so any tests for voltage and connectivity needs to take that into account. Why not earth the wire that goes to the switch and that should cause the element to heat up.

SD1too · 11th April 2022, 16:59

Quote:

Originally Posted by YMGF

... I have 12V on the yellow wire at the switch, indicating that all is well with the seat and wiring before that point.

Hi Michael,

As Dave remembers, the switching takes place in the negative leg of the circuit.

Remove the connector from one of the switches and bridge together pin 1 (yellow wire) and pin 5 (black wire). With the ignition on, does the seat heat up now?
If not, does it with the engine running?

Simon

YMGF · 12th April 2022, 06:19

Thanks both. It does seem strange doesn't it but as you say they are switched on the return so I'll bridge out at the switch and let you know how it goes.
Michael.

11th April 2022, 14:31	#1
YMGF Regular poster Rover 75 Saloon Join Date: Jul 2020 Location: Oxford Posts: 68 Thanks: 33 Thanked 12 Times in 8 Posts	Heated seats not functioning. Switches? Can you give me your thoughts please on my non-functioning heated seats. I expected to find either broken elements or thermostats. However, in both cases, I have 12V on the yellow wire at the switch, indicating that all is well with the seat and wiring before that point. I have checked the black wire on the switch for grounding, which it has. Both switches illuminate when seats switched on. Could it be failures on both switches? It seems unlikely but that's what it's pointing to. Unless I missing something staring me in the face, which is also possible. Thanks, Michael

11th April 2022, 15:08	#2
stocktake Vis Whiz Rover 75 2.5 auto Saloon Join Date: Jun 2007 Location: LEEDS Posts: 20,593 Thanks: 2,057 Thanked 3,056 Times in 1,621 Posts	Been an awful long time since I did any work on mine but seem to remember the switching on these is on the neg side so you could show 12v right through. Not known switches to fail but the same cannot be said for the under seat connections. Worth remembering the switches do have a timer on them so any tests for voltage and connectivity needs to take that into account. Why not earth the wire that goes to the switch and that should cause the element to heat up. __________________ Dave... Lost a few stones and a Gall Bladder and part of a bile duct and all of my dignity in the suppository incident

12th April 2022, 06:19	#4
YMGF Regular poster Rover 75 Saloon Join Date: Jul 2020 Location: Oxford Posts: 68 Thanks: 33 Thanked 12 Times in 8 Posts	Thanks both. It does seem strange doesn't it but as you say they are switched on the return so I'll bridge out at the switch and let you know how it goes. Michael.