Friday, 12 February 2016

Electrical issues, Temperature Gauge

Since i collected the truck i have noticed a few minor problems with electrical things not working at all or working incorrectly.  What i have spotted so far:

Temp gauge not working.
Oil light not working.
Alternator light not working.
Electronic cooling controller not working correctly

Temp Gauge

I verified that the temp gauge it's self was working first, then i identified the sensor on the engine block,  remember this is an air cooled engine so the gauge reads engine head temperature from a sensor directly in one of the cylinder heads.
There are two more similar sensors the signal a control box that controls the oil clutch of the engine cooling fan. The control box also monitors oil temperature
A simple test is to remove the wire from the sensor and short it to earth, the gauge should move to max,   It didn't.

So i started tracing the wire from the gauge to the sensor,  i used a tone sender that is used in the telecoms world, after a lot of dismantling and loom stripping i finally found the wire i was looking for,  of course it changed colour twice just to confuse me.   But i finally tracked it down, it was at the back of the engine instead of the front where it should be, just taped up in a loom not connected to anything. It took me the whole day to sort this one out.

Loom stripped to reveal the elusive wire.
 The wire where it shouldn't be.