Coolant and Heating Instrumentation malfunction

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nrxx: 1.9 DG  Had a non-functioning temp gauge for a while now. It did work but after a few weeks of low readings - nothing!

Bought a new sensor for the side of thermostat housing, checked for power, OK. Changed sensor but made no difference. Noticed another sensor hidden around the front of the thermostat housing (behind looking from rear). Should both of these be wired and if not, which one should be the coolant gauge sensor? Haynes appears to say that the one I changed should be a fuel injection temp sensor and that the one hidden round the front is the one I ned to check (obviously with a DG I don't have injection!).

Also... Do I need to remove the actual instrument cluster to check the multi-pin connector or just the cover?

AngeloEvs: The Temp Gauge Coolant sensor faces the front of the van. This is the one you need to change and make sure its the correct one identifiable by its colour. Multi-connector problems (if suspect) are best diagnosed with the dash out. The copper edge strips on the flexible part of the membrane panel need to be inspected and connection 6 to the Temp gauge needs to be checked for continuity. First, try shorting the Green/blue wire that connects to the temp sender (cab facing) to the engine block with a short section of wire and switching the ignition on. The gauge should start to rise after a few seconds and the coolant LED should flash continually.

There is an easier test of the gauge as follows (see picture below)...

You can test the gauge and its calibration by removing the module marked 43 from the fusebox. Using male spade connectors with a short link of wire (pic shows a 100 ohm resistor for testing calibration but wire is fine for a simple yes/no test) place them in the socket locations as shown. This will connect your gauge to earth and you won't have to crawl under the van to check the dash/gauge is OK.

Temp gauge testing AngEvs 01.jpg