Tdi Guy Posted February 10, 2015 Share Posted February 10, 2015 Purchased a 90 2.5td. Previous owner stated he tried to start it and it started to spark and smoke near the starter. I also see that the heavy gauge brown wires that go into the ignition switch have melted a bit at the terminals. What could have caused this. Not sure where to starts. Funny thing is I purchased another truck with the same setup 10 years ago for parts. It also had a complete electrical fire that started in the same area. Is this common with the 2.5td? Quote Link to comment Share on other sites More sharing options...
Maverik Posted February 10, 2015 Share Posted February 10, 2015 Common for most pre 1990's trucks, some pretty bad flaws in the wiring design, with the introduction of the Defender came relays and upgraded loom which was improved but still lacked... My 86 truck had part of the loom go up last year, turned out the circuit for the instrument lights wasn't fused at all... Quote Link to comment Share on other sites More sharing options...
pete3000 Posted February 10, 2015 Share Posted February 10, 2015 when I had the 2.5NAD in mine the two brown wires ran from the alternator, round the back of the engine, over the hot cylinder head in through the centre of the bulkhead, then pretty much straight to the ign switch from memory. Not a fuse in sight as it's the perm live, unfused until the purple appears. Quote Link to comment Share on other sites More sharing options...
deep Posted February 11, 2015 Share Posted February 11, 2015 I'm rewiring a 1987 110 at the moment and can confirm that the brown wire is unfused. In fact, it seems that the brown is a code for permanent live and all fuses are downstream from there! Which is reasonable if the wiring is nicely tucked up and not rubbing anywhere but, as soon as you start fiddling, you become vulnerable. You could put a heavy duty fuse on the starter solenoid connection (or wherever you take your feed from) but it's not likely you'd do that until the line met the bulkhead anyway. Quote Link to comment Share on other sites More sharing options...
Tdi Guy Posted February 11, 2015 Author Share Posted February 11, 2015 Yes, the brown wires go to the ign switch and they are a bit toasty. Wondering if I need a complete new harness. Quote Link to comment Share on other sites More sharing options...
pete3000 Posted February 11, 2015 Share Posted February 11, 2015 It's not just the 2 Browns that are unfused, the red/white back to the starter solenoid from the ign switch is unfused, along with the glowplug heater wiring or at least used to be on mine. When I chucked the 300tdi in I put a decent sized fuse block on the engine side of the bulkhead with and 80A and a 100A fuse in. The glowplug gained a timer relay and the red/white gained another relay Quote Link to comment Share on other sites More sharing options...
deep Posted February 11, 2015 Share Posted February 11, 2015 It's not just the 2 Browns that are unfused, the red/white back to the starter solenoid from the ign switch is unfused, along with the glowplug heater wiring or at least used to be on mine. When I chucked the 300tdi in I put a decent sized fuse block on the engine side of the bulkhead with and 80A and a 100A fuse in. The glowplug gained a timer relay and the red/white gained another relay Not a bad idea. I just put a 60amp push button ("momentary on") direct from brown to glow plugs, using a mental timer. A fuse before the button would be a good plan... Quote Link to comment Share on other sites More sharing options...
western Posted February 11, 2015 Share Posted February 11, 2015 the brown/red trace wire from ign switch to glowplugs on non tdi engines is live all the time too IIRC. it was prior to my '89 110 getting it's 200tdi engine. Quote Link to comment Share on other sites More sharing options...
Tdi Guy Posted February 12, 2015 Author Share Posted February 12, 2015 Yes, I would think that if you held the key on the glow plug cycle for too long you could heat up the wires and start a fire for sure don't you think? Quote Link to comment Share on other sites More sharing options...
western Posted February 13, 2015 Share Posted February 13, 2015 Yes, I would think that if you held the key on the glow plug cycle for too long you could heat up the wires and start a fire for sure don't you think? don't need to hold the key, the brown/red is 12v live the key move only diverts the 12v to another set of contacts so glowplugs are powered. I had a dash loom meltdown a few years ago, my front fog light switch live contact was touching somewhere it shouldn't have been & caused me to replace the complete dash/main loom, Quote Link to comment Share on other sites More sharing options...
Sandy Landy Posted February 13, 2015 Share Posted February 13, 2015 Is this the same issue with the 97 and up 300tdi Defenders? Do they have any unfused wires too? Thanks. Quote Link to comment Share on other sites More sharing options...
western Posted February 13, 2015 Share Posted February 13, 2015 every vehicle has unfused permanent live wires. Quote Link to comment Share on other sites More sharing options...
cackshifter Posted February 13, 2015 Share Posted February 13, 2015 Is this the same issue with the 97 and up 300tdi Defenders? Do they have any unfused wires too? Thanks. On those it all goes initially via the fuse box on the n/s of the bulkhead, except alternator to starter,battery to starter and a small feed to a diagnostics socket (and unofficial additions). Some of the fuses are pretty hefty though, so may not blow immediately unless seriously provoked, ie they'd probably happily fry a small wire downstream if it wasn't a massive fault current. Quote Link to comment Share on other sites More sharing options...
Sandy Landy Posted February 14, 2015 Share Posted February 14, 2015 On those it all goes initially via the fuse box on the n/s of the bulkhead, except alternator to starter,battery to starter and a small feed to a diagnostics socket (and unofficial additions). Some of the fuses are pretty hefty though, so may not blow immediately unless seriously provoked, ie they'd probably happily fry a small wire downstream if it wasn't a massive fault current. Thanks for the reply guys. I will go though the wiring on my 97 and will install fuses or breakers where needed. Some of the older BMWs have in line fuses on the main b+ close to the battery. There is an electronic breaker which I have seen in Canada for around 30 dollars. It has a key fob and serves as a short circuit breaker and a battery drain protector. It's really neat in a way because with the remote you can totally disable main power from the battery. Cheers. Quote Link to comment Share on other sites More sharing options...
simonr Posted February 14, 2015 Share Posted February 14, 2015 There is an electronic breaker which I have seen in Canada for around 30 dollars. It has a key fob and serves as a short circuit breaker and a battery drain protector. It's really neat in a way because with the remote you can totally disable main power from the battery. That sounds interesting! Post a link if you find it! Si Quote Link to comment Share on other sites More sharing options...
rod spink Posted February 14, 2015 Share Posted February 14, 2015 My 85 went up in smoke due to the stereo. Turns out it wasnt fused what so ever on that circuit. I had a very good look at the wiring and fitted fuses and relays where possible. Also removed any burnt cable spliced and hest shrink using heavy duty glued heat shrink. Quote Link to comment Share on other sites More sharing options...
bodumatau Posted February 14, 2015 Share Posted February 14, 2015 I was driving my '83 thru a tunnel and pulled out my phone charger out of the cigarette lighter, sparks flew, there I was at in heavy traffic in a tunnel at 100kmh with my dashboard trying to set itself on fire.... Nerve wracking stuff. Needless to say when I put my megasquirt in I will be adding a few fuses and relays... Quote Link to comment Share on other sites More sharing options...
Tdi Guy Posted February 15, 2015 Author Share Posted February 15, 2015 At least I'm not the only one. This is what I found. Switch is toast. Nothing else looks wrong. I was told the starter may have faulted as well Quote Link to comment Share on other sites More sharing options...
Tdi Guy Posted February 24, 2015 Author Share Posted February 24, 2015 So I replaced the ignition switch and now when I turn the key all I'm getting is the relay clicking behind the fuse panel. Nothing from the starter. Quote Link to comment Share on other sites More sharing options...
western Posted February 24, 2015 Share Posted February 24, 2015 that'll be the start relay, maybe the solenoid on the starter motor has been toasted as well. Quote Link to comment Share on other sites More sharing options...
Tdi Guy Posted February 24, 2015 Author Share Posted February 24, 2015 Yes, that's where I will be going next. Will pull the starter and take a look. Just too cold here in USA this month. -5deg all week Quote Link to comment Share on other sites More sharing options...
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