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HI FOLKS,
OUT IN MY DOLLY 1850 LAST NIGHT AND WHEN I PUT MY HEADLIGHTS ON THE TEMP GAUGE GOES UP AND VOLTS GO DOWN
I HAVE SINCE FOUND THAT EVEN THE HRW OR THE HEATER BLOWER CAUSE THE SAME FAULT.
Hi Tony, I've been thinking about this particular fault over the past few days as its quite interesting electrically.
The curious bit is " TEMP GAUGE GOES UP AND VOLTS GO DOWN ":
Now a couple of things. The temperature gauge is earthed via the engine block via the temp; sender and the thick black wire ( on my 1850 ) down to the battery earth.
Now since you have been able to check charging voltages etc; can you put the ignition on and measure the voltage from the engine block at the sender down to the battery earth.
( Reason being is that if there is a high resistance in this circuit it will back bias the temp; gauge ) There will be extra voltage in the 0V to the temp; gauge circuit. )
This won't affect the fuel gauge as that is earthed to the bodywork at the back of the car.
But turn extra items on and there may be extra paths that the return currents will find.
Slight problem : I would have thought this would have given you starter motor problems.
What voltage do you measure please ?
And a 2nd check: I know many Dolomites have had their wiring modified over the years.
Do you still have the original style instrument voltage regulator nailed to the engine side of the bulkhead ?
If so does it have one green wire and one Light Green wire on it?
And do the fuel gauge and the temp; gauge also have a light green wire going to each of them ?
If so this is good and the next stage of checking is more complicated and involves the alternator.
O.K. while you are looking at the alternator does it have 2 thick brown wires or 1 thick and one thin wire.?
( The reason being that the voltage at the voltmeter can drop under high current but the voltage at the alternator can be higher )
Another question : How much does the temp; gauge rise by and how by much do the volts gauge drop with say dipped lights on ?
Let us know on this and I'll run through some more measurements.
HTH,
Tony.