Club 80-90 Forums

You can test the sensor by running the van to normal temperature and, with a multimeter set to ohms, disconnect the wires at the sender and measure the resistance directly across the sender. A reading of around 100 ohms indicates the sensor is OK and the temp gauge needle should be about midway when you connect the wires back onto the sensor then engine re started.

If the reading is higher (150ohms and above) then either the sender is faulty or the coolant temperature is below normal (faulty thermostat, not fitted, etc) or there is insufficient coolant in the thermostat housing.

Spade connectors can be a problem and the wires become brittle and break at the crimp connection inside the insulation. Renew any that look suspect.

If the sender resistance is correct at around 100ohms then you will need to check the wiring in the engine bay. The brown wire is chassis earth and, with a multimeter set to ohms, you need to check that it does connect to earth. Aternatively, get a piece of wire and link the brown sender terminal directly to the engine block and see if that cures the problem.

Trace the brown wire to the earth point and check/renew the connections, spade connectors, etc.

Trace the red/yellow, I think it terminates in a black box in the engine bay, I would check the multi connectors by separating them and spray with WD40 or contact cleaner.

If the wires are hard and brittle , replace them , the cores will be black and high resistance

If the temp sender wires are like that , then it would be a good idea to also check the oil pressure sender wires too ( two brown wires into a twin white spade junction just near to the thermostat housing , or the next issue will be the BoD waking you up as you leave the motorway !

These thirty plus year old wires don’t like the constant hot cold hot cold shaking and vibrating they are doing !

Thanks all, sender, o ring etc ordered. Worst wiring replaced but I need to do more. Who sells the big plugs that go into the senders or shall I just use to spades?

New sensor installed, some wire replaced, temp gauge now working, perhaps a bit higher than previously but certainly responds swiftly. My interest now moves to another electrical query...see new post!

Many thanks all.