<!--quoteo(post=161500:date=Thu 6th May 2010, 06:10 PM:name=SteveK)-->QUOTE(SteveK @ Thu 6th May 2010, 06:10 PM) <{POST_SNAPBACK}><!--quotec-->One small question, when you say 'Normally open' does this mean that the contacts close when the pressure is low. Just wondering about the fail safe mode should the wire fall off or become broken.<!--QuoteEnd--><!--QuoteEEnd-->
Normally open will be the position of the contacts when the unit has no supply to it or, as shown by the wiring diagram, when the oil pressure is low. When the ignition is 'on' the low pressure indicator will show. When the engine starts the pressure increases and the contacts close. The light then goes out.
If a wire comes off the light wont initially illuminate when the ignition is on.
It looks like a good mod to me, better than an oil gauge. [img]style_emoticons/<#EMO_DIR#>/dry.gif[/img]
<!--quoteo(post=161500:date=Thu 6th May 2010, 06:10 PM:name=SteveK)-->QUOTE(SteveK @ Thu 6th May 2010, 06:10 PM) <{POST_SNAPBACK}><!--quotec-->One small question, when you say 'Normally open' does this mean that the contacts close when the pressure is low. Just wondering about the fail safe mode should the wire fall off or become broken.<!--QuoteEnd--><!--QuoteEEnd-->
How is works is thus: The pressure switch contacts are open when oil pressure is low. When the engine pumps up the presssure the contacts close and short the led to earth thus turning it off. The resisitor is to current limit the circuit to about 18 ma through the switch. The led is already earthed, so if the wire to the switch comes off the led will light as the led is connecting the resistor to earth.
LED's are like a dead short diode, this is why the 560 ohm resistor is there. It dissapates about 300 mw so, a 1 or 2 watt resistor is ok here.
I made one up so you have three leads from the led. Power from a live that goes on when ignition is on, earth and switch. Red Black and blue. this is for a normally open sensor when there is no oil pressure.
<!--quoteo(post=161122:date=Mon 3rd May 2010, 08:57 PM:name=hammerman)-->QUOTE(hammerman @ Mon 3rd May 2010, 08:57 PM) <{POST_SNAPBACK}><!--quotec-->Guide now finished.
Hope it is useful to everyone.<!--QuoteEnd--><!--QuoteEEnd-->
Hi Lee and Hammerman,
great job [img]style_emoticons/<#EMO_DIR#>/good.gif[/img] [img]style_emoticons/<#EMO_DIR#>/good.gif[/img] [img]style_emoticons/<#EMO_DIR#>/good.gif[/img]
Received the switch yesterday but due to missing time will take some time to mount it following this perfect guide.
Wil, this is fantastic. Thanks for going to the trouble
During my year or so hear, I have taken advantage of enhancements/additions/mods shared and supplied by Carpedians. Very often the items have been put on my trolley in the garage for dealing with later. Time to fit all these bits and pieces and with guidance like this life is made so much easier.... Brought the switch from Lee in earlier to remind myself of what I needed to do and found this thread!!
Thanks again....and to all the others that keep supplying the invaluable advice, help, ideas, expertise etc
I completed this procedure last weekend. Thanks to leehenty, and this excellent guide everything went well.
My lamp is a little different. I used a panel lamp with a holder that fits through the front of the hole, but there was no way to secure the locking nut.
I used a soldering iron to melt a small hole through the blanking piece that is discarded if you use rubber lamp holders, and used a cable tie around the wires, to hold the lamp in place. Not a perfect solution but it works.
I took my power from the pilot lamp above the headlamp. I didd this or easy access, in case I ever need to disconnect the +ve due to a short.
I fitted an oil pressure gauge a few years ago with a banjo at the same place discussed above. At the top of the crank case feed pipe that goes to the back of the head.
I have acquired the Intermotor 50770 switch and found a friend to turn it down to 10 mm for me on his lathe.
Now I also looked at the altetnatives which also feature a 1.4mm hole for the oil to flow through. The Intermotor switch/bolt has a much bigger hole though.
The hole diameter seems to matter as it restricts the oil flow to the head to some extent. As I cannot access the original Photobucket files I remain wondering how you worked around this potential issue?
Quote:The hole diameter seems to matter as it restricts the oil flow to the head to some extent. As I cannot access the original Photobucket files I remain wondering how you worked around this potential issue?
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The banjo bolt at the other end of the oil pipe has the same part number so has the smaller hole to still regulate.
Tdm 850 Oil Pressure Switch Installation Guide
![[Image: 12mm-dashboard-warning-lights-l.jpg]](http://www.bikermart.co.uk/prodimages/12mm-dashboard-warning-lights-l.jpg)
![[Image: 65CBFAA7-2F43-4020-9079-2289AC4E3EB9_zpsmczh5yoh.jpg]](http://i73.photobucket.com/albums/i231/drewpy_1/TDM/65CBFAA7-2F43-4020-9079-2289AC4E3EB9_zpsmczh5yoh.jpg)
