SLROC Forum

Hi guys my dad has got a Td5 defender, it has a couple of issues but the one I can't figure out is the temp gauge.

So here goes when you turn the ignition on and engine is cold the temp gauge is reading right in the middle as if its been running. As the engine heats up the gauge reading goes down to cold.

Anyone have any ideas???

Thanks Bill

Possible faulty temp. sender unit, replace it with a new one.

Hi bill mines had similar issues the temp guage was going up and down with the revs and various other things it was caused by a bad earth at the ecu under the drivers seat i ran a heavy cable from the earth stud across to the battery and that cured the issue

Is this a new to him defender or new ecu

I had this issue when I got a later ecu fitted to my 10P TD5 defender. Same symptoms, I checked the engine temp with a friends Hawkeye and the gauge was reading backwards, turns out I had a disco configured ecu as the original installer had only disco software. Went to Es Alternators and got the ecu re flashed with defender software and never had a issue again. Maybe worth plugging in a nanocom, Hawkeye or terrafirmas tool (£100) to prove the gauge.

If your handy with a multimeter you can get true temperature readings from the temp sensor and cross referencing the resistance with the graph for the fitted temp sensor. bit of a stab in the dark but it might be on this link but you will have to double check the fitted temp sensors ID number and search Bosch website.

http://rb-aa.bosch.com/boaasocs/modules-pdf/Bosch_AA_Sensoren_PDFGen.dll?db=BOAAMDB02PRD7&MV_ID=886&CL_ID=20&Prod_ID=330&filename=0281002209.pdf

Greg