MattSuffolk Posted March 7, 2017 Report Share Posted March 7, 2017 Hi all, I have a 2001 1.0 Lupo with a very strange electrical problem, It is an intermittent fault (always handy). When the ignition is turned on, the dash warning lights will not come on (in fact the clock and odometer go off) and the starter will not engage, as if there has been total electrical failure, everything is basically dead. Switching the key off it remains in the 'dead' state, repeated turning on and off of the ignition will eventually clear the fault, it will then start and run fine as if nothing ever happened. It doesn't happen every time, it can go days without an issue or it can do it 3/4 times in a day. Having probed it with a multi-meter I have managed to shed some more light on it, when it is in the 'dead' state the voltage at the fag lighter (easiest place to measure it) shows only 6v (or thereabouts), but measuring directly at the battery it is still 12v. Also, if I measure across the negative post of the battery to the positive of the fag lighter, 12v, this leads me to think the issue is on the earth side somewhere (the meter shows a 6v ish reading when measuring -ve of battery to -ve of fag lighter). I have changed the alternator, tried a different battery, tried a different ignition switch, checked and cleaned the main battery earth lead (to body and engine), checked the 3 main earth points in front of the gear lever, checked the +ve cables at the battery, alternator, starter and the bus bar to the right of the pedals. I am now totally lost, the fact that it seems so 'switchable', it either it works or it doesn't, makes me think that it is a component causing the fault rather than a poor connection. Has anyone heard of anything similar before, and ideas what I should be looking for?? I have tried many searches with no luck! Many thanks Matt Quote Link to comment Share on other sites More sharing options...
Rich Posted March 7, 2017 Report Share Posted March 7, 2017 relay 100? faulty ignition switch? start tracing. Quote Link to comment Share on other sites More sharing options...
Sausage Posted March 7, 2017 Report Share Posted March 7, 2017 If you cant see anything obvious with earths etc, then pull the fuses out one at a time and try it to isolate bits of the loom, so pull a fuse try key replace fuse (after inspecting it and contacts) and then repeat on the next one if there's no change in behaviour. Doing them one by one means they go back in the right slot too. It sounds like a relay on it's last legs but the voltage drop sounds like a short or bad earth. Quote Link to comment Share on other sites More sharing options...
mk2 Posted March 7, 2017 Report Share Posted March 7, 2017 If you're getting only six volts, it would typically mean that the power is being interrupted somewhere by a high impedance contact. So that tells me that somewhere there is a contact that is arcing away, reducing the volts. Could be ignition switch. Could be a relay contact. Could be a loom connection. Could be loose fuse. In a nutshell, anywhere where power flows through to power the main electrical 'ignition-on' circuit. I'd start by assuming the earth is ok, then tracing the + voltage along the route that leads to the ignition switch. You'll need to pull all the plastic interior panels off under the steering column to do that.... Rich might be right. Could be worth simply swapping over that relay as a quick test. Quote Link to comment Share on other sites More sharing options...
MattSuffolk Posted March 8, 2017 Author Report Share Posted March 8, 2017 Thanks for the replies, I will try what has been suggested and report back Quote Link to comment Share on other sites More sharing options...
lupolad Posted February 15, 2023 Report Share Posted February 15, 2023 (edited) Hi, I realise this is over 5 years old but just in case you are still on the forum, did you discover the fault? I have very similar and tearing my hair out (if I had any ) Edit - just seen you have not been active since 2017 Edited February 15, 2023 by lupolad Quote Link to comment Share on other sites More sharing options...
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