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1969 Giulia GT Junior, with 2 litre conversion
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Discussion Starter #1 (Edited)
Hi. I have a 1969 GT Junior, which now blows fuse #6 when ever the ignition switch is turned on.

In my car there is only a single pink wire coming from the cold side of the fuse, which feeds the dash gauges. I've not made any changes to the car recently, other than late in 2019 I fitted some LED BA9S bulbs in the water temp and fuel gauges and also the speedometer, which when tested were a significant improvement on the standard bulbs. The lights are on a separate fuse in the fuse board. At the time, fuse #6 was intact and did not blow.

I came to start the car about a week ago, and went to crank the car over with the plugs removed to ensure there was oil pressure prior to the first start. The (veglia) oil pressure gauge in the side of the tacho didn't move and the low oil pressure warning light also didn't light. The fuel gauge also didn't move. I checked fuse 6, which had blown. I swapped out another known good fuse, which instantly blew when I turned the key suggesting a short to ground.

I've now tried the following:

1) with all 4 dash connectors (oil pressure gauge, warning lights in speedo, water temp and fuel level) disconnected, there is no connectivity between the cold side of fuse 6 and ground (I'm using the steering column as a ground reference point).

2) with the fuel level gauge connected, and again placing the multimeter between the cold side of fuse 6 and ground there is no beep on the continuity tester, but a resistance of around 75 ohms, which is commensurate with half a tank of fuel. The fact that resistance is greater than zero is good as this suggests no short to ground.

3) when gradually connecting the other 4 connector blocks, the resistance falls to around 5 ohms total. This is confusing me, as I thought resistance was additive?

4) I've tested the individual feeds into the back of the connector blocks for the oil pressure warning light, the oil pressure sender, water temp sender and found that in isolation, all of these have a resistance of 0.6 ohms along the cable (i.e. these are not broken) and when removed from their various senders are not shorting to ground anywhere.

Short (if you pardon the pun) of just throwing fuses at the situation, I'm running out of ideas.

To confirm, my dash lights are on another circuit. My reverse lights are on another circuit. All my vehicle lights are on alternative circuits.

Any suggestions as to what to try next?
 

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I guess you have + connected to earth, and the fuse blows.

Did you tried conecting one by one, with trying to start the engine between each step ? You will see then on which circuit is the bad contact.

perhaps an electric wire has moved or been nibbled by a small animal ?
 
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