External temperature sensor

brianj100 · 22nd January 2010, 09:02

I fitted a replacement temp sensor to my 75 tourer last week, but it has not cured the problem.
The problem is that the read out will go from as low as -30 at start up, and gradually up to as high as +20 over say a 15 mile journey. I did the battery re-boot but this seems to have no affect either.
Any ideas?
Brian

Greeners · 22nd January 2010, 09:06

welcome along

Check the wiring carefully, especially near the sensor. It's likely that the insulation is broken and the conductor inside has corroded

brianj100 · 22nd January 2010, 10:14

Greeners, thanks for the welcome.
From your experience, is it likely that the insulation in the plug is breaking down or could it be the wiring insulation. If it's the plug are replacements available?
I suppose that this is a bumper off job.
Thanks

WeeMan · 22nd January 2010, 10:28

Having the same problem as you!. Have replaced sensor..... and still getting same mad readings. Have been advised through forum that chaffed wiring is the likely cause, but can't get at it just now as its too cold

.

brianj100 · 4th April 2010, 15:39

I finally got round to fixing the problem with my external temperature sensor. It was indeed the wiring that had chaffed but not near the sensor itself. The wiring loom had become detached from the clips that should hold it close to the moulding of the bumper so that it hang down onto the undertray. The insulation on four of the wires that run to the multi plug had been rubbed through, with the orange one from the temp sensor completely worn through the wiring (hence the -30 C open circuit).
After replacing the worn through wiring and re-insulating I have cable tied the loom back into the securing clips to stop it dropping down in future.
Display is now reading 10.5 C.

22nd January 2010, 09:02	#1
brianj100 Newbie Rover 75 Tourer Join Date: Dec 2009 Location: Burnhill Green Posts: 11 Thanks: 0 Thanked 2 Times in 2 Posts	External temperature sensor I fitted a replacement temp sensor to my 75 tourer last week, but it has not cured the problem. The problem is that the read out will go from as low as -30 at start up, and gradually up to as high as +20 over say a 15 mile journey. I did the battery re-boot but this seems to have no affect either. Any ideas? Brian

22nd January 2010, 09:06	#2
Greeners Moderator MG-ZTT Join Date: Mar 2007 Location: Ware, Herts Posts: 19,798 Thanks: 161 Thanked 1,249 Times in 1,036 Posts	welcome along Check the wiring carefully, especially near the sensor. It's likely that the insulation is broken and the conductor inside has corroded __________________ *David* Impecunity is the mother of ingenuity Useful how to's for common problems Car Of The Month Jan 2014 [SatNav Power Down] [Coolant Level] [SatNav Repair] [Diesel Non Starting] [Paint Codes] [Rear Light Seals] [Reversing Light Switch] [Bleeding Brakes][Sunroof Drain] [Early ZT's][Instrument Pack Diagnostics][ATC Diagnostics]

22nd January 2010, 10:28	#4
WeeMan Posted a thing or two Mazda MX5, BMW 520i Join Date: Feb 2007 Location: Sunny Ayrshire Posts: 1,498 Thanks: 2 Thanked 4 Times in 4 Posts	Having the same problem as you!. Have replaced sensor..... and still getting same mad readings. Have been advised through forum that chaffed wiring is the likely cause, but can't get at it just now as its too cold . __________________ http://www.sloganizer.net/en/style8,ZTT.png

22nd January 2010, 10:14	#3
brianj100 Newbie Rover 75 Tourer Join Date: Dec 2009 Location: Burnhill Green Posts: 11 Thanks: 0 Thanked 2 Times in 2 Posts	Greeners, thanks for the welcome. From your experience, is it likely that the insulation in the plug is breaking down or could it be the wiring insulation. If it's the plug are replacements available? I suppose that this is a bumper off job. Thanks

4th April 2010, 15:39	#5
brianj100 Newbie Rover 75 Tourer Join Date: Dec 2009 Location: Burnhill Green Posts: 11 Thanks: 0 Thanked 2 Times in 2 Posts	I finally got round to fixing the problem with my external temperature sensor. It was indeed the wiring that had chaffed but not near the sensor itself. The wiring loom had become detached from the clips that should hold it close to the moulding of the bumper so that it hang down onto the undertray. The insulation on four of the wires that run to the multi plug had been rubbed through, with the orange one from the temp sensor completely worn through the wiring (hence the -30 C open circuit). After replacing the worn through wiring and re-insulating I have cable tied the loom back into the securing clips to stop it dropping down in future. Display is now reading 10.5 C.