So my neutral light has a problem, it never worked by the way since I bought it, it's the one cable version Checked so far: Fuses, oke Light bulb oke Wiring, Tested on the positive side of the battery and light illuminated. Replaced sensor with a new one, no result. The starter will go with his side stand down in gear, but fuel pump doesn't prime so no real start, but this has got me thinking of some mods done by the previous owner. Found two wires on the left side near the seat under the air box that are soldered together, when the solder is loose the fuel pump doesn't prime?? Also from the side stand switch there are three wires coded 1,2 and 3, following it to the connector it will continue with no 2 and 3, no1 is discontinued. Maybe this has something to do with it. Any suggestions?? Cheers Nick
Could be the gearbox is not pressing the switch in and out correctly, I had that on my 748SPS but a new switch did sort the problem out.
I'm confused, new switch and no results.... The wire that's going into the crankcase, does it have 12volt originally? Or is it switching on the negative on the bike? I'm missing something here.....[emoji53]
I'll be honest, I cannot remember now. I was riding along one day and either the neutral wouldn't come on or vice versa. I realised it was a problem straight away but had a brand new switch in stock so a quick swap out cured the problem. Do you have a wiring diagram at all as even a different model with the same switch setup will show you how it is wired. I remember checking some looms once and that was one of the things that was different between early and later model 748 looms I seem to remember. Apologies if this is a bit vague but a bit of wire tracing has sorted out the few problems I have had in the past. The only other thing you might need to check is that the washer behind the neutral switch is at the correct "setting" and not causing the switch to not pick up on the gearbox neutral position.
Does the neutral switch have spacer washers?As in,if a thicker spacer has been used,might that stop the light coming on?Even with a different switch.
Out of interest I checked the 2002 78R parts manual and a washer is listed. The part number is 420.2.001.OA. This should then set the switch in the correct position. The photo shows the neutral switch as having a two pin connector.
Red, thx. The washer is there, also tried it without the washer, to be sure it is in contact with the drum. No success. My loom has only the one pin connector? No 12v on the connector though. I followed the loom but there were no mods made on it, except the one under the left side of the air box that's soldered, when disconnect the fuel pump doesn't prime? Any further tips are welcome. Will give an update when there is progress. Nick
Do you have a wiring diagram, I don't have one for a 748R but I do have one for the base models. I'll see what the layout is. I seem to remember fitting a two pin plug switch on a one pin loom and all I had to do was earth the switch to the engine case. I take you your earths between loom and frame and engine and frame are good. Does your neutral light show up if you put power to the live side of the bulb?
Just checked a wiring diagram for a 748SPS which has a two wire neutral switch. The earth for the neutral is tied in to a number of earths that all wire into the earth on the turn signal relay. The power side comes from fuse four on the the fuse box counting from the top fuse. It too is linked in to the turn signal relay on the power side. Attached is the wiring diagram if that helps.
So did a little more troubleshooting, found a wiring diagram for the post 2001 bikes, one wire neutral switch. It's correct that the switch is switching on the earth of the bike, it means that we need a plus and minus on the light bulb, that's the problem, I do not have it, wonder how it ever worked, but that's another thing. Acc the diagram it needs to be a blue + wire and a yl/gr minus wire. I have a yello gr but not a blue one, it's a black one?? Will search more tonight. Any ideas red? Cheers Nick
Black or Brown usually signifies earth on Ducati's but not always!!, indicators being one example. Ducati seem to wire their bikes slightly oddly at times. Can you trace a wire from the turn signal indicator to the neutral light if that is where the positive power side comes from as per earlier models. Possibly the best thing might be to trace the pilot light for neutral back through the loom and see where it ends up. If it worked before and all else seems good then it looks like a wiring problem. Do you know where the neutral light is tied into on the fuse block. Unfortunately the wiring diagram won't enlarge enough to read it. Can you blow it up more and maybe post again?
Mine has the 2-wire switch that switches the positive, although I modified it to switch the negative (Translogic dash needs a negative signal for neutral indication). However I've looked at the later (1-wire) wiring diagram and the wire from the neutral switch runs directly (through the large round connector) to the light, whereas the positive is fed from a positive (shared with the oil pressure switch and also passes through the large round connector) in the dash - does the oil pressure light work? First thing to check is short the wire on the switch to earth/negative to check the switch and feed to the bulb, if this works then the switch is no good, if not then either the connector, the bulb or the positive feed is no good. I would suggest opening the large connector (near battery) and checking for corrosion/cleaning etc. If you have a multimeter, check the connections at and between the connector and the dash.
Just read through from the start, in the first post you say you have tested to the positive side of the battery and it lights up? as has been mentioned the switch has to be spaced correctly on some models of ducati, you say you have tried without the washer and with, it might need a thicker one, I tend to wind the switch right in without a washer and then gradually turn it out until it works. Not sure about the later models but some don't need spacer washes as the contact point on the gearbox has a neoprene type insert where the switch makes contact only allowing it to earth when in neutral. It should work if you just earth the wire to the casing to test. Steve
@Birdie. Yes I tried it on the positive of the battery and it light up, I can explain it right now because it has a ground wire on the light. It isn't really shimmed, it's more a copper gasket. Older models two wire types needs to be shimmed. The newer models just need a copper gasket. Will try tonight, I will replace the black wire (ground) for a positive wire, we'll see were we at than. Keep you posted.
Fixed!!! Cut the blue wire from the red light (not used but wired and with 12v) than cut the ground from the neutral, soldered the blue and black together and neutral light is back! Wondering if it ever worked by the way! Thanks for the help red and birdie!!
Glad you got it sorted. I've never got round to sorting mine. It works fine until the bike is warm and then it is on all the time in all gears. However it gets slightly brighter when neutral is selected. I think it may need a thicker washer.
