tommac Posted May 20, 2008 Share Posted May 20, 2008 Hi all, Had a look at the defender last night- the fuelgauge works but we dont get a light when its low- had a looksee at the top of the tank- only 2 wires coming into and onto the sender unit- yet 3 connectors on it- is this right? Its a 94 300 tdi by the way? Cheers Quote Link to comment Share on other sites More sharing options...
DaveB Posted May 20, 2008 Share Posted May 20, 2008 I think it depends on the model. Some Defenders did not have the 'low fuel' connection on the sender or the third wire into the connector block. I think it may have been standard on CSWs but my basic truck cab has only the two wires even though there is a block for three. Quote Link to comment Share on other sites More sharing options...
western Posted May 20, 2008 Share Posted May 20, 2008 Yep, not all later vehicles have the 'low fuel' warning light, if you want it to work run a wire from the rear terminal to the light on the dash, there's 2 types of sender unit 1 with the low fuel connection & the other without, sounds like a previous owner has swapped the sender at some point. Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted May 21, 2008 Share Posted May 21, 2008 Or maybe just another Defender wiring stuff-up. Like the positive earth side lights. Quote Link to comment Share on other sites More sharing options...
jimmy_neutron Posted May 24, 2008 Share Posted May 24, 2008 Hi all, Had a look at the defender last night- the fuelgauge works but we dont get a light when its low- had a looksee at the top of the tank- only 2 wires coming into and onto the sender unit- yet 3 connectors on it- is this right? Its a 94 300 tdi by the way? Cheers Don't be running extra wires !!!!!! The fuel sender jobbie should only have 2 wires connected to it. A green wire with a female spade on the back of your fuel gauge gets the +ve feed for the whole fuel gauging. The green wire with a male spade on it on the back of the fuel gauge runs to the VDO wiper on your intank sender. The other connector on your intank sender (black i think if i remember rightly) goes to earth. The intank sender kinda gives a varying resistance which causes the needle on the gauge to go up and down. On to the low fuel light... there is a box in behind the dash that also looks at this varying resistance. I forgotten what its called but i'm sure ya get the idea. This is what puts your low fuel level light on. But start with the simple... change the bulb. Quote Link to comment Share on other sites More sharing options...
G_Cam Posted July 18, 2008 Share Posted July 18, 2008 Don't be running extra wires !!!!!!The fuel sender jobbie should only have 2 wires connected to it. A green wire with a female spade on the back of your fuel gauge gets the +ve feed for the whole fuel gauging. The green wire with a male spade on it on the back of the fuel gauge runs to the VDO wiper on your intank sender. The other connector on your intank sender (black i think if i remember rightly) goes to earth. The intank sender kinda gives a varying resistance which causes the needle on the gauge to go up and down. On to the low fuel light... there is a box in behind the dash that also looks at this varying resistance. I forgotten what its called but i'm sure ya get the idea. This is what puts your low fuel level light on. But start with the simple... change the bulb. I feel for you - its very annoying!! I'm having a NIGHTMARE with my Fuel gauge and low level warning light ...the gauge stopped working (always showing full) and now the warning light has packed up!!! I have changed the sender (2 wire) but to no effect...... can anyone tell me what the resistance should read when the sender is on Empty/Quarter/Half/three-quarters and FULL? HELP!! I'm running out of patience - even had it into an auto-electrician and he has not been able to fix it!!! my only fuel 'gauge' is when I splutter to a halt.... Quote Link to comment Share on other sites More sharing options...
western Posted July 19, 2008 Share Posted July 19, 2008 Don't be running extra wires !!!!!!The fuel sender jobbie should only have 2 wires connected to it. A green wire with a female spade on the back of your fuel gauge gets the +ve feed for the whole fuel gauging. The green wire with a male spade on it on the back of the fuel gauge runs to the VDO wiper on your intank sender. The other connector on your intank sender (black i think if i remember rightly) goes to earth. The intank sender kinda gives a varying resistance which causes the needle on the gauge to go up and down. On to the low fuel light... there is a box in behind the dash that also looks at this varying resistance. I forgotten what its called but i'm sure ya get the idea. This is what puts your low fuel level light on. But start with the simple... change the bulb. Sender has 3 wires on certain age vehicles, later vehicles don't have the low fuel connection on the tank sender,so only has 2 connections, a feed to the gauge & a earth,the low fuel light relay behind the dash is controlled by the tank sender unit, no fuel light icon on the warning light panel means it's not fitted to that vehicle. Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted July 19, 2008 Share Posted July 19, 2008 Graham, Did you check that the low level warning light bulb is OK ? Mo Quote Link to comment Share on other sites More sharing options...
western Posted July 19, 2008 Share Posted July 19, 2008 swap the bulb with a known good one & check you got the wires one the correct terminals at the sender unit, if the spade terminals are connected wrong the gauge will show full deflection. Quote Link to comment Share on other sites More sharing options...
G_Cam Posted July 19, 2008 Share Posted July 19, 2008 Graham,Did you check that the low level warning light bulb is OK ? Mo Hi Mo - i have checked it.....the bulb is on all the time....and the gauge is showing full.....a total contradiction!!!! Grrrrrrrrrrrr Quote Link to comment Share on other sites More sharing options...
western Posted July 19, 2008 Share Posted July 19, 2008 or maybe the sender float has a leak & has sunk to the bottom of the tank & therefore would show a full indication. Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted July 20, 2008 Share Posted July 20, 2008 erm, wouldn't that show empty then Ralph ? Mo Quote Link to comment Share on other sites More sharing options...
western Posted July 20, 2008 Share Posted July 20, 2008 Doh!! yes it would. Quote Link to comment Share on other sites More sharing options...
G_Cam Posted July 22, 2008 Share Posted July 22, 2008 Hi All a NEW TWIST................ I have now got my fuel warning light working again........... I pulled the sender....moved it up & down...it works OK...... after EXTENSIVE head scratching... it appears that it had been re-fitted in such a way that the float was 'getting caught' on the fuel pickup pipe. I have a HD long range baffled tank in place - so its a bit of a fiddle to get the sender in at the correct angle. The person who had been working on it had even snapped one of the 4 set screws that hold the sender in place .... (another hours work for me & my dad!) The fuel gauge is DEFIANTLY not working - it reads 'full' all the time...but I guess it could just be defective after all these years? The resistance from the sender was the same at the sender as it was across the gauge. (Aprox: 330 full; 110 half full; 20 empty - measured in Ohms). Graham Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted July 22, 2008 Share Posted July 22, 2008 WKW90 had this problem with the gauge reading which we found was down to a duff gauge. Substitution resolved the problem. Mo Quote Link to comment Share on other sites More sharing options...
jimmy_neutron Posted July 23, 2008 Share Posted July 23, 2008 Hi Mo- i have checked it.....the bulb is on all the time....and the gauge is showing full.....a total contradiction!!!! Grrrrrrrrrrrr That sounds like a short to earth. When the ignition is on 12vdc is sent permenantly to the low fuel light. It is the box behing the dash the does the switching on the -ve side to determine whether the light is on or off. If the tank always readsfull then take both wires off the sender as a test and see if it makes any difference. If it stays showing full the trace back the short wire by wire until you end up crawling behind the dash. IIRC the higher the resistance the emptier the tank. Short to earth gives full tank. Quote Link to comment Share on other sites More sharing options...
G_Cam Posted July 27, 2008 Share Posted July 27, 2008 WKW90 had this problem with the gauge reading which we found was down to a duff gauge. Substitution resolved the problem.Mo Thanks Mo I fitted another gauge last night......and it was EXACTLY THE SAME ie showing full....but the tank is not full! I'm getting SO FRUSTRATED with this!!!!!! Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted July 27, 2008 Share Posted July 27, 2008 OK Graham, you've changed the sender and you've changed the gauge with no joy. That leaves the wire from the sender to the gauge. Have you tried substituting this with another length of wire yet ? If not, that's your next step. Good luck Mo Quote Link to comment Share on other sites More sharing options...
Guest diesel_jim Posted July 27, 2008 Share Posted July 27, 2008 Remember also that there should be two "earths" on the guages.... one goes onto the spade connector on the back, and the other is on the actual case itself. usually on a ring terminal fitted under one of the little thumbscrews that hold the retaining bracket in place. they loop to all the guages, then go to earth. if this is missing, then showing "full" or "really hot" or "about 25volts" (on a battery guage) is the outcome. Quote Link to comment Share on other sites More sharing options...
Ryan Posted July 27, 2008 Share Posted July 27, 2008 [Hijack alert] Talking about the warning light - at what point does/should it come on? Mine comes on just as the needle starts to get into the orange band on the fuel gauge - is this correct? How much fuel should be/is left at that stage? [Hijack alert/] Quote Link to comment Share on other sites More sharing options...
western Posted July 27, 2008 Share Posted July 27, 2008 yep, that's about right, with about 10 litres in the tank. Quote Link to comment Share on other sites More sharing options...
Ryan Posted July 27, 2008 Share Posted July 27, 2008 Cheers Ralph. Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted July 27, 2008 Share Posted July 27, 2008 You've got a good one Ryan, unless you have a TD5 fuel gauge the light usually starts coming on at about 3/4 of a tank Mo Quote Link to comment Share on other sites More sharing options...
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