• Ciao Guest - You’ve landed at the ultimate Guzzi site. NEW FORUM REGISTRATIONS REQUIRE EMAIL ACTIVATION - CHECK YOUR SPAM FOLDER - Use the CONTACT above if you need help. New to the forum? For all new members, we require ONE post in the Introductions section at the bottom, in order to post in most of the other sections. ALWAYS TRY A SEARCH BEFORE STARTING A NEW TOPIC - Most questions you may have, have likely been already answered. DON'T BE A DRIVE-BY POSTER: As a common courtesy, check back in and reply within 24 hours, or your post will be deleted. Note there's decades of heavily experienced Guzzi professionals on this site, all whom happily give endless amounts of their VALUABLE time for free; BE COURTEOUS AND RESPECTFUL!
  • There is ZERO tolerance on personal attacks and ANY HYPERLINKS to PRODUCT(S) or other competing website(s), including personal pages, social media or other Forums. This ALSO INCLUDES ECU DIAGnostic software, questions and mapping. We work very hard to offer commercially supported products and to keep info relevant here. First offense is a note, second is a warning, third time will get you banned from the site. We don't have the time to chase repeat (and ignorant) offenders. This is NOT a social media platform; It's an ad-free, privately funded website, in small help with user donations. Be sure to see the GTM STORE link above; ALL product purchases help support the site, or you can upgrade your Forum profile or DONATE via the link above.
  • Be sure to see the GTM STORE link also above for our 700+ product inventory, including OEM parts and many of our 100% Made-in-SoCal-USA GTM products and engine kits. In SoCal? Click the SERVICE tab above for the best in service, tires, tuning and installation of our products or custom work, and don't miss our GT MotoCycles® (not) art on the BUILDS tab above. WE'RE HERE ONLINE ONLY - NO PHONE CALLS MADE OR RECEIVED - DO NOT EMAIL AND ASK QUESTIONS OR ASK TO CALL YOU.
  • Like the new V100, GuzziTech is full throttle into the future! We're now running on an all-new server and we've updated our Forum software. The visual differences are obvious, but hopefully you'll notice the super-fast speed. If you notice any glitches or have any issues, please post on the Site Support section at the bottom. If you haven't yet, please upgrade your account which is covered in the Site Support section or via the DONATE tab above, which gives you full site access including the DOWNLOADS section. We really appreciate every $ and your support to keep this site ad-free. Create an account, sign in, upgrade your account, and enjoy. See you on the road in 2024.

No Brake light/Headlight

2Laner

Cruisin' Guzzisti
Joined
Aug 1, 2009
Messages
105
Location
Auburn, Illinois
About 30 minutes into a trip to Arkansas my riding partner flagged me down. No brake light. Pulled off, checked fuses, all good and found out no headlight either. Troubleshooting problem appeared to be main ignition switch not suppling voltage to relay 4. Had continuity but no voltage. I put a jumper on fuse C to D so I could continue trip. Not sure why but license plate bulb stayed on and ran down battery that night, Jumped it and then disconnected battery whenever we stopped after that. Anyway, anyone have experience with no headlight/brake light and offer any insight. I tried swapping the 2 similar relays and I just checked on price of main switch. Ouch. $208.00 Finish trip, even beat the rain gods. Wonderful twisties in Arkansas and southern Missouri. 08 Sport 54,000 miles. Thanks
 
Looking at what I think is the closes schematic for your bike, the only common component appears to be the ignition switch as you stated. You may just have to bite the bullet for one. Also I hope you know your user code as I doubt the keys you have will work with a new switch. I suggest consulting with a knowledgeable dealer to remedy your issue.
 
Well worth spraying some contact cleaner into the switch and operating it several times to see if you can clean them. Disconnect battery first though.
 
I had this and other problems. Check the six pin plug from the ignition switch, mine was coroded. I replaced it with a waterproof deutz
plug.
 
Wow, thanks chippy. Will do. I have always been leary about spraying electronic contact cleaner into main switch as I assumed it used a dielectric gel lube. I did try it with no positive result. Has anyone ever tried a disable of switch? I removed bottom of switch for a continuity/voltage check. What is a deutz plug anyway? My follow up question was a concern about about the key. My limited understanding was that replacing the main switch should not affect the programed "code" on the key to the immobilizer( (?) in the main speedometer/tach assembly.
 
deutz is just a brand name of a waterproof plug. I just replaced the 6 pin plug you will find if you follow the wires down . Mind you the tank needs to come off i also took the airbox out. the plug is amongst the hoses and wiring on the left side. Good luck.
 
One of he problems with the standard Guzzi wiring is that the current required to operate the starter motor solenoid is routed through the ignition switch. This current is something like 25A for a short period, but the switch contacts are not rated above 16 Amps. Thus those contacts could burn out if there is a resistive connection in there to start with. The Startus Interruptus mod avoids this issue.
 
I am no electrical engineer and do not have time at the moment to look at the wiring diagram but isn't there a relay to the lights from the switch? If so try swapping it out with another and see if you get lights. How about the starter button. On a lot of bikes the starter button has a set of contacts that disable the lights while depressed. I have seen those corrode up and turn off the lights. Lots of time just flicking it several times will cure the problem.
 
A couple of days ago I finally had some time to spend on this. Yea Chippy. I was pleasantly surprised that the connector to harness was culprit. My bad on normal maintenance I'm afraid. Electrical spray cleaner restored bike to normal brake/headlight operation. I went ahead and sprayed all the connectors I could find. Going to lube them up with dielectric grease soon. One more gremlin now. Battery measured at terminals indicates 12.8 volts. Instrument cluster indicates 11.8? Several times I had to hold start button for an extended time for bike to fire. Yes I did the relay mod a long time ago.
 
2Laner, it is common for the voltage at the dash to read less than a multi meter at the battery. However, the reluctance to start may indicate a battery on the way out. Have you cleaned the battery connections lately? They are prone to a black form of corrosion forming that reduces and sometimes stops current flow.
 
2Laner, as John says there is always a difference between measured at the battery and what is displayed on the dash. Mine is 0.8V lower on the dash than the real voltage at the battery. The difference is caused by the minimalist size of wires plus the connections in the wire's path which contribute to an ohmic path, thereby the difference. It just is (Italian Electrics).

Mine dash reads 13.0 or 13.1 V when running (this is half an hour after the last start) while running, which is in reality 13.8 V or 13.9 V at the battery.

The main earth for these bikes (CARC) is behind the starter motor cover. This is not a good spot, nor is it a solid connection for a main earth. I and a few others have moved the main earth point (2 x lugs) onto the bell housing bolts just above the original point. This works wonders and is worth doing, but does take some time to do - the lug hole needs to be made slightly larger and I would suggest a tapered reamer is the best tool. Don't be tempted to use an electric drill as the lugs are copper and will probably grab and may cause damage to the wires, lugs or your fingers.
 
For that I would use a small round file. Get one with a taper of about the right size and you can use it as a reamer.
I removed the starter cover on my Norge, and used a decent bolt to take the earth connection. With the lower fairing, you don't see the starter anyway so it just gets in the way.
 
Back
Top