Identifing the relays

[Kannon]

My '02 LeMans lost the headlight, tail light, brake light and horn. The schematic tells me that the horn and lights are powered from the light relay which gets power from the N.C. contact of the start relay. I am having difficulty identifing the relays, there are 5 of them and I don't know which one is which, they arn't labeled.

 

I have pulled each relay and bench tested by powering them up and testing with an ohmeter, they all test OK. If I knew which relay was which I could test and provide power directly to the relay socket terminals and bypass the relays altogether.

 

One other thing I might mention, and I don't know if this is related - - while riding yesterday I noticed the tach acting strange intermittantly. When restarting after engine shutdown I had no tach for a few minutes, then it would work fine, also somtimes it would peg on start up then go back to normal after a few minutes

 

Has anyone here had a similar problem?

 

Thanks,

 

Bruce

[Guest ratchethack]

Hi Bruce

 

Front to back: START, LIGHTS, NEUTRAL, ECU, EFI.

 

Hope this helps.

[Kannon]

Thanks Ratchethack, I'm gonna' tag each one of 'em now.

I'll let you know how the job goes - -

 

Thanks,

[Kannon]

Found the problem, it was the light relay. It 'bout drove me crazy testing it though. When I originaly tested the relays, I hooked up my power supply and ohmeter with the relay terminals pointing up and all relays functioned fine. However after Ratchethack told me which relay was which I was able to bypass the relays by using jumpers and found everything to work as it should - - It HAD TO BE the relay, so I substituted the neutral relay for the light relay and it worked. THEN I retested the light relay holding it in the terminal down position as it would be when on the bike and it didn't work - I think I learned somthing.

 

Thanks again,

[docc]

Good news!

 

It's certainly worth switching to upgraded relays if you have not done so already (OMRON, GEI, or Bosch)

 

Lot's of old threads with links and such.

[Guest ratchethack]

Good on ya, Bruce. Besides being notoriously finicky in their application in the Guzzi, we tend to forget that these are not solid state, but "electro-mechanical" devices, subject to effects of gravity WRT how they're positioned when testing. Thanks for the reminder.

 

FWIW, having used Siemens, Tyco, Bosch, GEI, and Omron -- the only ones that haven't given me trouble are Omron. I personally recommend Omron relays from Forum Member and Pro Engineer John Mickowski, see his link here:

 

http://www.motratech.com/Motratech/MGRC20.html

 

-- don't miss his relay study comparison page.

[Skeeve]

On a completely unrelated topic, would routing the power for the lights thru the normally closed contact on the starter relay [which would be open while starting, right?] automagically cut out the drain on the battery from the lights while starting? [This isn't relevant to my Guzzi, I'm thinking about my SV650 commuter bike, which doesn't cut the lights for starting, making the battery prone to cold weather & age-related failure...]

 

TIA

[Greg Field]

Isn't it wired that way already?

[Skeeve]

Isn't it wired that way already?

 

My SV? No, the dumb thing tries to run the headlight & the starter at the same time...

[raz]

Well if it has a starter relay wired more or less like the V11, the answer is yes. If the lights doesn't have an own relay you should fix that as well. Apart from giving better light this will ensure you don't get side effects like overtaxing the starter relay (depending on what else is on it).

[luhbo]

Do not wire it like on the V11. It has a relay for the head lights, but only in theory. The switch is situated between starter relais and bulb, dumb enough. Long ago there were some posts here about this topic. For some (the usual suspects so to say) an additional relay to release the light switch turned the night literally into bright daylight

 

Hubert

[docc]

My '02 LeMans lost the headlight, tail light, brake light and horn.

 

The tail light still burns if the light relay is bad. It's on a circuit with no relay along with the 'dipped' light and instrument lights. Kind of a 'limp home' mode.

 

Curiously, if the headlamp, brake light, and horns go out and she will not restart: it is fuse 5 (not a relay). (or the clutch switch . . .)