HendrixsWhiteStratReturns Posted June 6, 2021 Share Posted June 6, 2021 MorningI have an old enormous red warning light in my dash which I am replacing (with one that doesn't look like it came of the control panel of Thunderbird 2!!)Wires to the old unit are black and black&white as shown in pic. Does anyone know which of those two is the 12v feed to the battery please ?Cheers Link to comment Share on other sites More sharing options...
OldAndrewE Posted June 6, 2021 Share Posted June 6, 2021 Most (if not all) crossflow sevens did not have a warning light as standard, just a pressure gauge as far as I know. If this is wired in the normal way then as you say one wire on the bulb will be 12V feed and the other wire will go to the pressure switch on the engine (the switch provides the earth which is switched off when pressure is high enough). Check the colour of the wire on the switch - the other one will be the 12V feed. At a guess I would say the black is earth (switch) and the black/white is feed Link to comment Share on other sites More sharing options...
HendrixsWhiteStratReturns Posted June 6, 2021 Author Share Posted June 6, 2021 Thanks Andrew - appreciate the post. Link to comment Share on other sites More sharing options...
rkeywood Posted June 6, 2021 Share Posted June 6, 2021 My '89 X-flow is wired green for the gauge, red/white to the light, white/brown to the sensor and black earth. No switch originally Link to comment Share on other sites More sharing options...
OldAndrewE Posted June 6, 2021 Share Posted June 6, 2021 I assume the light you mention is the instrument panel light and you have an electric pressure gauge Link to comment Share on other sites More sharing options...
OldAndrewE Posted June 6, 2021 Share Posted June 6, 2021 Further to #2 above the normal colours would be white 12V feed from the ignition switch (only live when ignition on) and white/brown to the pressure switch. Link to comment Share on other sites More sharing options...
rkeywood Posted June 6, 2021 Share Posted June 6, 2021 Wiring for original illuminated electric gauge. R/W daisy chains along the instrument light connections. Green is the live that daisy chains along the instruments. I've had a quick scan of the wiring diagram (Jan 88) and it looks like white at the ignition and green off the fuse. Link to comment Share on other sites More sharing options...
OldAndrewE Posted June 6, 2021 Share Posted June 6, 2021 R/W is the standard colour for the panel lights and on older systems Green is the live feed to the instruments that comes from the voltage stabilizer (supplies a steady 10V) . Cannot see a voltage stabilizer on the post '87 diagram but may have missed it.Anyway none of this helps the OP as he is asking about an oil pressure warning light Link to comment Share on other sites More sharing options...
John Vine Posted June 6, 2021 Share Posted June 6, 2021 Assuming the light is ON when the engine isn't running, can you not use a multimeter to test which wire is 12v?JV Link to comment Share on other sites More sharing options...
HendrixsWhiteStratReturns Posted June 6, 2021 Author Share Posted June 6, 2021 Evening gentsall done and working, many thanks ! Link to comment Share on other sites More sharing options...
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