Installing a voltometer

[camfairweather]

My F-300 did not come with the clock/inclometer/voltometer unit, so I bought one from a wrecker.

The clock and inclineometer are working fine, but the voltmeter refuses to work (although the light does come on)

Looking through the forums, I see someone else had the same problem last year but unfortunately there was no follow up on whether they found out what needed to be done to make the voltometer live.

Anyone got any ideas?
There was mention of having to 'connect a wire' somewhere.

Interestingly, I used my multimeter to check the current flow and the socket and measured 12v when the car power was off, but droped to nothing when the car was started. I did wonder if I had the clock and voltometer socket around the wrong way but no change when I swapped them over.

I reversed the polarity on the the voltometer just to see what would happen, and to my surprise it jumped to 12volts when the car was off, but would drop back to zero after the car was started. I assume it should have been the other way around with no reading when the car was off, but a reading when the car was on.

Cheers for any help anyone can offer.

[murcod]

Have you looked at the wiring diagrams in the manuals?

There appears to be only two wires going to the voltmeter- the +ve is red wire with a blue stripe and the negative is a black wire. The red/ blue wire comes straight from the "ign on" IG circuit and the black is a chassis earth.

Worse case you'll just have to run two suitable wires tapped into suitable source wires.

[camfairweather]

Thanks for that.

I disconnected one of the connectors and ran it to earth. Works perfectly now (except it's a little out of calibration - reads 12 volts as 9).

Thanks again.

[camfairweather]

Oh and for the record,

It was the black and white striped cable to earth.