RogerB Posted August 19, 2017 Share Posted August 19, 2017 Further to my last post I have purchased the mechanical oil pressure gauge and warning switch/light kit from Think Automotive. Having fitted the gauge I am trying to figure out how to connect up the warning light using the existing wiring from the removed electronic gauge. I found a wiring diagram online for the k series however it doesn't seem to make sense with respect to the pressure gauge. I would like to avoid running another wire between light and switch if possible.Roger. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted August 19, 2017 Member Share Posted August 19, 2017 Can you post a link to the information in the kit, or a picture of it?Have you got a wiring diagram for your 7, and, if not, would you like one?Do you have a multimeter?Jonathan Link to comment Share on other sites More sharing options...
Wrightpayne Posted August 20, 2017 Share Posted August 20, 2017 Another job on my 'to do' list. I was planning to pick up a live feed under the dash and take down to the switch. Then a wire from switch to bulb then bulb to earth.There are several unused wires in the loom plug in the engine bay above the steering column, usually tie wrapped to the chassis diagonal. It may be possible to pick up a switched live here and use the original gauge wire to get back to the dash. Wiring diagram and multimeter should work it out!Ian Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted August 20, 2017 Leadership Team Share Posted August 20, 2017 Use the original white/brown wire that ran from the oil pressure sender to the gauge.In the engine bay, at the pressure switch end attach the white/brown to one terminal of the switch, connect the other terminal to a good earth using black "1mm thin wall cable".Behind the dash, connect the white/brown to one side of your new warning light, then connect the second terminal to a fused live, use the "ignition switched" green cable's under the dash, possibly there will be one that already ran to your original oil pressure gauge.Stu. Link to comment Share on other sites More sharing options...
elie boone Posted August 20, 2017 Share Posted August 20, 2017 You can use the green live feed from the old electrical gauge, and the sender wire in the same plug as your earth trough the low oil pressure sender ( Yellow/red on a 2005 K series ) Link to comment Share on other sites More sharing options...
Wrightpayne Posted August 20, 2017 Share Posted August 20, 2017 Stu / Elie,I thought the same after pondering my earlier post. The gauge had a live feed and wire to the engine bay so simply re-use existing with a bit of wire to extend to the switch.Thinking some more, would it make sense to have the low pressure switch behind the dash or will the signal display quicker if located nearer to the engine?Ian Link to comment Share on other sites More sharing options...
elie boone Posted August 20, 2017 Share Posted August 20, 2017 Why would u put the sensor under the dash ? it makes quit a long tube to do that. Keep it simple and just reuse the existing wiring. I use a side repeater as Idiot light. Link to comment Share on other sites More sharing options...
Wrightpayne Posted August 20, 2017 Share Posted August 20, 2017 My pressure switch is tee'd into the tube that goes to the mechanical OP gauge so moving the T point would keep the wiring contained under the dash.Ian Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted August 20, 2017 Leadership Team Share Posted August 20, 2017 It would be slower to respond under the dash. Link to comment Share on other sites More sharing options...
RogerB Posted August 20, 2017 Author Share Posted August 20, 2017 Thanks Guys most of what you say seems to make sense. And is basically what I have already tried with my multimeter. I measured the voltage between green and brown/white at the dash with the black and brown/white wires connected to the terminals on the pressure switch. So far so good however the voltage didn't drop to zero when I started the engine. I thought the pressure switch must be faulty, The switch is Ok though as I checked for by testing the resistance across it with engine stopped and then running. I notice at the switch the wires that where connected to the sender had a single black (-ve Earth) however two brown/white (+ve) from gauge. As for the location of the pressure switch it does make sense to have it closer to the engine. And that is how the kit comes from think automotive with a short length of braided hose connected to the T piece where the switch is fitted, then plastic hose up to the mech gauge at the dash. Guests have just arrived which is holding me up getting back for another go ! Roger. Link to comment Share on other sites More sharing options...
RogerB Posted August 21, 2017 Author Share Posted August 21, 2017 Thanks Stu,I'm not sure what I was playing at with the multimeter, however it works fine with the light using all existing wiring. Roger. Link to comment Share on other sites More sharing options...
RogerB Posted August 21, 2017 Author Share Posted August 21, 2017 Thanks Stu,I'm not sure what I was playing at with the multimeter, however it works fine with the light using all existing wiring. Roger. Link to comment Share on other sites More sharing options...
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