cookie64 Posted November 12, 2013 Share Posted November 12, 2013 Hi Ive got to the point where i desperately need to fit a coolant level sensor on my 300tdi as i dont want to spend another £2K on my engine so i searched online and saw bits of info about using part no PRC7925 (Range rover 200tdi Header tank sensor/cap) and thought thats a brilliant idea so managed to find and order a brand new genuine one for £26 brill its arrived but how do i wire it up errrr confused tommy here so i searched online agaibn and can see bits of information all over the place but can seem to piece together a full solution so.... Can anybody Help Please????? i believe ralph has done this mod in the past, can you remember how you did it???? thanks in advance tom Quote Link to comment Share on other sites More sharing options...
Puffernutter Posted November 12, 2013 Share Posted November 12, 2013 Having overheated my engine and replaced it, I did exactly the same mod to prevent it happening again! The problem is that the Range Rover header tank sensor has a resistor in circuit, so it's not a simple case of wiring it up to a light. I bought a purpose built unit (there is a thread on here somewhere!) in the Discovery area. A friend used the sensor to drive a transistor and then a lamp. His worked just as well. If I get a chance tonight I'll dig out the circuits. Cheers Peter Quote Link to comment Share on other sites More sharing options...
cookie64 Posted November 12, 2013 Author Share Posted November 12, 2013 thanks pete Quote Link to comment Share on other sites More sharing options...
cookie64 Posted November 12, 2013 Author Share Posted November 12, 2013 ok just found this http://forums.lr4x4.com/index.php?showtopic=86322&hl=prc7925 clearly a better search originally would have pulled this up for me durr they show this part http://www.ebay.co.uk/itm/230684501787?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649 £8 sounds just the biscuit for me Quote Link to comment Share on other sites More sharing options...
Puffernutter Posted November 12, 2013 Share Posted November 12, 2013 I had found this thread - http://forum.difflock.com/viewtopic.php?t=1712 But as it is so old, the images are long gone. You'd have to contact one of the contributors to see if the information could be sent to you. The "Metrobus" part might be just as simple! Cheers Peter Quote Link to comment Share on other sites More sharing options...
mmgemini Posted November 12, 2013 Share Posted November 12, 2013 Here is the ORIGINAL post...Or maybe the follow on.... http://forum.difflock.com/viewtopic.php?t=10972&highlight=300tdi+coolant+loss+sensor Quote Link to comment Share on other sites More sharing options...
MuddyWinny Posted November 12, 2013 Share Posted November 12, 2013 Hello, I have been looking at the very same thing and bought sensor PRC7925. With the sensor in one hand and a multi meter in the other I'm finding that the sensor doesn't have any resistance when the level is high (i.e. switch closed) and is effectively open circuit when the level is low. The thing that seems to be in doubt is the current that the switch can cope with? The basic circuit I'm looking at creating the attached circuit Switch open (coolant low) light is on Switch closed (coolant level fine): light off S1 is the coolant switch. R1 is 1k ohm. I can't remember the transistor off the top of my head. It would be easy to put a 'test' switch in series with the coolant sensor to make sure it works but I'm trying to come up with a circuit that has the warning light on for a few seconds when the ignition is turned on (there are a number of ways of dong it but come down to using a capacitor or the field terminal from the alternator). Not sure how much this helps you but I'm happy to share the finished circuit. Regards Mark Quote Link to comment Share on other sites More sharing options...
Puffernutter Posted November 12, 2013 Share Posted November 12, 2013 Transistor could be a BC107, BC108 or BC109, any general purpose NPN. Make LS1 a LED. Cheers Peter Quote Link to comment Share on other sites More sharing options...
4b4 Posted November 12, 2013 Share Posted November 12, 2013 £8 ebay jobbie is sold out - anyone know of a similar simple piece of plug and play kit for us "electrical idiots" Quote Link to comment Share on other sites More sharing options...
cookie64 Posted November 12, 2013 Author Share Posted November 12, 2013 sorry i may have grabbed the last one there i like marks idea of the lamp coming on for a few seconds during ignition to prove the light just like abs lights etc Quote Link to comment Share on other sites More sharing options...
Puffernutter Posted November 12, 2013 Share Posted November 12, 2013 I just had a push button that bridged out the coolant sensor and triggered (in my case) the indicator and the alarm. That gave me confidence that it woudl work - granted it wasn't automatic but it was good enough for me. The circuit shown earlier should be easy to knock up. I have some transistors and LEDs lying around if it helps. Cheers Peter Quote Link to comment Share on other sites More sharing options...
jbs Posted November 12, 2013 Share Posted November 12, 2013 I've linked a R/R coolant sensor lid to this and it works very well: http://www.ebay.co.uk/itm/Low-Coolant-Level-Alarm-12V-/170927068334?pt=UK_Sound_Vision_Other&hash=item27cc0c14ae More or less plug and play John Quote Link to comment Share on other sites More sharing options...
dailysleaze Posted November 12, 2013 Share Posted November 12, 2013 Here's what i did http://forums.lr4x4.com/index.php?showtopic=77747 Quote Link to comment Share on other sites More sharing options...
Puffernutter Posted November 12, 2013 Share Posted November 12, 2013 And Sronefisk is my neighbour and I suggested he did a simple transistor circuit - by then I'd bought a ready made one! I have transistors if anybody wants/needs them. Cheers Peter Quote Link to comment Share on other sites More sharing options...
western Posted November 12, 2013 Share Posted November 12, 2013 my coolant level unit & float cap on my 200tdi in my reply in this thread http://forums.lr4x4.com/index.php?showtopic=49268 plus other options Quote Link to comment Share on other sites More sharing options...
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