Gabes Electrical house of pain

[GabrielGoes]

whats up guys i am in need of some advice, any if possible... My rear brake light does not light up how it should when my handlebar switch is "on", now it lights up just perfectly when ever i press the brakes like the front and rear but the constant rear light for nightime use does not come on at all! cars cant see me untill i press my brake basically, i am totally lost i looked at all of my connections and all seems to be fine, i used a new bulb but nothing.. wrong bulb maybe? it was working before... any advice or pointers on where to look specifically would be great. i really dont want to have to take my whole harness out and re-do every little thing that would be some hard work... one thing i noticed is that my ground that goes to my - on the battery got a little hot and i can see it melted a little bit ( i think the wire was to thin to support all of my grounds.. also my guage lights dont work eaither, this is killing me, my bike is stripped downnn and its got me downn thanks for reading!

[Nessism]

Did you check the fuse box?

[GabrielGoes]

Did you check the fuse box?

my bike doesnt have a fuse box sorry i didnt mention, its a 1978 gs750e....
i am just confused because i dont get how the brake light will work when pressed and how the constant light doesnt go on... i dont know if its in the headlamp unit area or what i think im just gonna have to go full blown surgery on my bike again

[GabrielGoes]

some part of me really wants to just trash this bike and get a dependable new age sport bike but another part me says those bikes are just plastic toys and the bike i have now is just so damn good when shes running, the sound and look, the wheels, everything just so great but this electrical is just killing me and makes me want to punch this bike in the face

[simon kuether]

I think you're in a bit of strife there old mate .
You must have a fuse box .
Find that , then come back .........................

Cheers , Simon .

[GabrielGoes]

I think you're in a bit of strife there old mate .
You must have a fuse box .
Find that , then come back .........................

Cheers , Simon .

i really dont think i have one! eaither my bike (a 1978') doesnt come with it at all or the p/o took it out, seriously i dont think my bike has a fuse box... my bike is like my right arm that isnt working lol thanks for the feedback guys any reply even a rude reply makes me feel good lol, misery loves company!

[Andrei]

You asked about the bulb you needed, it should have two filaments and three leads going to it, two hot wires and a common ground, one filament comes on with the brake switches and the other is your running light, something to keep in mind when you're tracing wires. Also, your fuse box should be behind one of your side panels, it takes the old glass fuses, you'll know it when you see it.

[Steve]

If I recall correctly, many of the GS bikes before '79 or '80 did not have multiple fuses in a "box". There was a single fuse that was probably clipped to the frame somewhere near the battery.

About the only thing that would be common to the tail light and the instrument lights would be the ignition switch. It has multiple contacts, some will take power from the battery or r/r (whichever is supplying at the moment) then distrubute to others that will send to various parts of the bike. One of those contacts goes to the lights, but I can't tell you right now what color wire will be connected to those contacts. Use a test light or voltmeter to verify that you have power on the wires, then trace the wire in either direction to find the problem.

.

[simon kuether]

It wasn't meant to be rude , a little sarcastic maybe (just my "offbeat" sense of humour - no offence meant old mate) .
And I stand corrected , now I know something else aboot these loverly old girls .
Hang in there , it'll come together .
You're being blooded into the brotherhood of the GS .
Each step of the way leads to enlightenment , ............ or doom .
Pass all the challenges , electrical , carbs , brakes ,shims .............. et al , and you'll become that legend reveeered in pubs for miles .
" 'E knows a bit about zookies" , they'll say .
Are you LEGEND ? Or are you mere mortal ? Can you walk the hazardous path to enlightenment ...............
If you do , the old girl will start every time , and go , and go , and go .
Oil change , chain adjust/maint , cable lube and you're good to go , any where , anytime .
If you have the time , do one "bit" at a time .
Sort you're electrics , totally . Find and check every connection at every switch etc , and in the harness . I find a good way of proving the harness and other electrical components , is to get a diagram (enlarged a bit is good) and a highlighter and colour each wire as you trace it from end to end . Check it with a multi meter . Repair every connection . I despise bullet connectors and believe they are a pox on bikekind , but to each their own . Replace them where possible with spade types (using the correct tools) and you'll prevent a lot of headaches down the track .
As part of this , check ALL your earths (grounds) . They've all got to be clean , tight and with a thin smeer of vaseline (white petroleum jelly) is good .
Routing the harness is worth messing about with as well . Make sure it doesn't get pinched (or stretched) at the steering head , make sure the tank and seat dont crush it , etc .
You'll find , after doing all this , that your electrics are no longer a mystery to be feared . They'll be as reliable and as strong as any bike out there . If you do get a fault , you'll know its a device (or a connection at a device) and not the wiring itself .
If you do searches , you'll probably find most of the info you need . If not , ask away .........

Cheers , Simon .

[GabrielGoes]

It wasn't meant to be rude , a little sarcastic maybe (just my "offbeat" sense of humour - no offence meant old mate) .
And I stand corrected , now I know something else aboot these loverly old girls .
Hang in there , it'll come together .
You're being blooded into the brotherhood of the GS .
Each step of the way leads to enlightenment , ............ or doom .
Pass all the challenges , electrical , carbs , brakes ,shims .............. et al , and you'll become that legend reveeered in pubs for miles .
" 'E knows a bit about zookies" , they'll say .
Are you LEGEND ? Or are you mere mortal ? Can you walk the hazardous path to enlightenment ...............
If you do , the old girl will start every time , and go , and go , and go .
Oil change , chain adjust/maint , cable lube and you're good to go , any where , anytime .
If you have the time , do one "bit" at a time .
Sort you're electrics , totally . Find and check every connection at every switch etc , and in the harness . I find a good way of proving the harness and other electrical components , is to get a diagram (enlarged a bit is good) and a highlighter and colour each wire as you trace it from end to end . Check it with a multi meter . Repair every connection . I despise bullet connectors and believe they are a pox on bikekind , but to each their own . Replace them where possible with spade types (using the correct tools) and you'll prevent a lot of headaches down the track .
As part of this , check ALL your earths (grounds) . They've all got to be clean , tight and with a thin smeer of vaseline (white petroleum jelly) is good .
Routing the harness is worth messing about with as well . Make sure it doesn't get pinched (or stretched) at the steering head , make sure the tank and seat dont crush it , etc .
You'll find , after doing all this , that your electrics are no longer a mystery to be feared . They'll be as reliable and as strong as any bike out there . If you do get a fault , you'll know its a device (or a connection at a device) and not the wiring itself .
If you do searches , you'll probably find most of the info you need . If not , ask away .........

Cheers , Simon .

hey thanks man that really gives me motivation, i was really in a bad mood because about a month ago i ripped everything out and soldered everything 12 hours straight through the night to what i thought was "perfect" but i guess some things dont last forever, one things for certain is that i am going to get spade connectors instead of having to cut wires and re-solder them like i am facing right now... and i totally wasnt reffering to you when i said rude comments! i was just saying basically that ANY reply would make me feel better lol! i am going to try and tackle this project before friday without TOTALLY being ****ed off while doing so lol...

[TheCafeKid]

You need to get a wiring diagram. You need a manual.

I do believe BassCliff has one for your bike (as well as MOST of the GSs) on his website. The tail lamp (not the brake lamp) is run off a BROWN wire. Obviously, you need to make sure that the connectors under the tail cowl are all CLEAN and connected... If thats not the problem, you need to break out the diagram and start following the wire back and looking for breaks, or other issues. A Volt/Ohm meter would be handy in this instance, and is almost a necessity if you plan on keeping your bike maintained. Besides your current (no pun intended) problem, there will be other electrical issues on ANY GS that will need attended to. It was the weakest point of the design (and MOST other bikes of the day as well..thank god you dont own a Triumph or BSA...)

The circuit that feeds your tail lamp (at least on MOST GSes, they were pretty much all the same) also feeds your gauge cluster bulbs... If those are out, you really need to take a look at whats going on there..

I hate to state the obvious as well, but since this is a two filament bulb/socket, you may want to check that the bulb is installed correctly. There is only one way it can go in, but Ive seen idiot POs shove em in there the wrong way. If you get to testing, and find that your lamp socket is at fault, let me know, I have quite a few of those 77-79 "E" model 750 tail lamps around. I may even have a wiring harness or two in decent shape..

[dardoonk]

Give me your email if you need a copy of the service manual.

[koolaid_kid]

Oddly enough, BikeBAndit's parts fiche shows a fuse box under the left side cover:

http://www.bikebandit.com/1978-suzuki-motorcycle-gs750ec/o/m6102

[GabrielGoes]

You need to get a wiring diagram. You need a manual.

I do believe BassCliff has one for your bike (as well as MOST of the GSs) on his website. The tail lamp (not the brake lamp) is run off a BROWN wire. Obviously, you need to make sure that the connectors under the tail cowl are all CLEAN and connected... If thats not the problem, you need to break out the diagram and start following the wire back and looking for breaks, or other issues. A Volt/Ohm meter would be handy in this instance, and is almost a necessity if you plan on keeping your bike maintained. Besides your current (no pun intended) problem, there will be other electrical issues on ANY GS that will need attended to. It was the weakest point of the design (and MOST other bikes of the day as well..thank god you dont own a Triumph or BSA...)

The circuit that feeds your tail lamp (at least on MOST GSes, they were pretty much all the same) also feeds your gauge cluster bulbs... If those are out, you really need to take a look at whats going on there..

I hate to state the obvious as well, but since this is a two filament bulb/socket, you may want to check that the bulb is installed correctly. There is only one way it can go in, but Ive seen idiot POs shove em in there the wrong way. If you get to testing, and find that your lamp socket is at fault, let me know, I have quite a few of those 77-79 "E" model 750 tail lamps around. I may even have a wiring harness or two in decent shape..

thanks dude i just got a testor today and am going to try and test things out... one thing thats funny is i go to turn my key on today and the horn just blasted right in my ear! lol i have some testing to do!! thnaks and i will definitly let you know if i need the harness or something, thanks

[GabrielGoes]

hey guys i got a quick question for this brake light thing... when you take the brake light bulb out theres two wires that touch to the bulb ends, i tested one of the wires is "hot" when the brakes are pressed, but the other wire is "dead", should this "dead" wire be the one thats constantly "hot"? im guessing it has to be always hot because the rear driving light should always be on, and the other wire should only become hot when the brake is used? correct me if im wrong