Honda CX 500 Forum banner
1 - 19 of 19 Posts

·
Registered
Joined
·
38 Posts
Discussion Starter · #1 ·
I stripped the fairing and rear storage off the Mongrel, which left a need for a new headlight and turn signals. It's a budget build, so I went with some cheap Ebay stuff. Ill use it as long as it lasts. I have only dabbled with wiring, so I need some assistance on getting these things installed. I have the wiring diagram for the '78, so I know where to plug into. I just need help on which wires are which on the headlight/turn signals.

Purchased a set of dual headlights.(scrambler look) They have 2 sets a wires as the pic below shows. No instructions. Anyone have any experience with these? How can I figure out the difference between the wires?



Also got these turn signals. Made sure to get some with three wires to support running lights, but again, how can I figure out the difference? Any help would be great. Thanks!!

 

·
Registered
Joined
·
1,637 Posts
If you have a 12 volt battery charger protected by a circuit breaker that can put out at least 4 amps , not a trickle charger, you can put the +12 volt and - 12 volt leads to the wires to see what they are, if both lights glow you have two +12 volt wires to that bulb(hi+low). Write it down in your FSM or somewhere for future reference. Clamp the charger leads to a plastic pen, plastic ruler, block of wood, just not metal or something to keep them apart. Low beam is dimmer than high, marker lights are dimmer than signal lights. You could use your multi -meter set to ohms[R= resistance in ohms , E=volts, here 12 , P=watts use this formula; R=E squared /P , an example 12 volts sq.= 144 so R= 144/60 watts (typical hi beam light) would make R = to 2.618 ohms] lower numbers means higher power draw, a brighter light. 0 ohms is good for ground checks. In these type of lights black not green is usually the ground. Don't do this off your battery unless a 5 amp fuse is in inline with your probes. Hope it helps.
 

·
Registered
Joined
·
376 Posts
I almost guarantee that black is ground on your signals your running light is green and turn signal red. although the green and red can be interchanged depending on what circuit you are hooking up to it. couldn't tell you on the headlights although i'm betting that brown single one is ground. not sure why the lights have 4 wires going to them.
 

·
Registered
Joined
·
38 Posts
Discussion Starter · #6 ·
I did a little more research and found this description on another ebay auction similar to the one I got.

"Wiring: 8 Wire Set Up (2x High Beam Wire, 2x Low Beam Wire, 2x Daytime Running Wire, and 2x Ground Wire)"

So I am guessing that I use Steve1's method of figuring out the resistance of each? Since the original headlight only had high/low, will I need to just eliminate the running light connection?

Going to try some more googling and hopefully find someone else that has already figured this out.
 

·
Registered
Joined
·
41 Posts
I did a little more research and found this description on another ebay auction similar to the one I got.

"Wiring: 8 Wire Set Up (2x High Beam Wire, 2x Low Beam Wire, 2x Daytime Running Wire, and 2x Ground Wire)"

So I am guessing that I use Steve1's method of figuring out the resistance of each? Since the original headlight only had high/low, will I need to just eliminate the running light connection?

Going to try some more googling and hopefully find someone else that has already figured this out.
Why not just check the bulb side?
 

·
Registered
Joined
·
38 Posts
Discussion Starter · #8 ·
Yes fega, that would be the smart thing huh?

So I took the light apart. Found that the brown wire is for a 2nd, smaller bulb inside the housing. My guess is a daylight running light? The main bulb is an H4 type, so I was able to figure you the color scheme from there. Black-Ground, White-High Beam, Yellow-Low Beam.

Now that I have the headlights figured out, on to turn signals. I took those apart as well and figured out they are dual filliment lights. Black-Ground, Red and Green-Power. On the rear signals where I don't need the running lights, I will just combine the Red and Green.

Things are finally looking up with the electrical!!! I have a couple more questions that I hope someone can help me with.

I have all the wires tracked down except for a couple. I have 2 black wires that I am not sure where they go. One comes out of the group of cables by the red connector that has all the dash light wires.




The other one comes out of the main harness with a green and solid brown cable. I know the green is ground, but I am unsure about the black and brown.




Last, I believe is the turn signal flasher relay. On the wiring diagram is shows it needs a black wire. Does one of the black wires above connect on the relay?

 

·
Registered
Joined
·
371 Posts
...it looks like the turn relay to me. but usually as nolimitz sez, it's not in bucket.... Grey wire supports this given wiring diagram ... yes, Black wire need be connected.

Brown is only used for tailight and parking lamp in headlight.... That cutoff one is for the unused forward parking bulb in headlamp. Usually it's an empty connector on north american models- someone has chopped it off.
Look at my signature. It may help.
 

·
Registered
Joined
·
3,804 Posts
nolimitz is correct, that is the 7v regulator.
The turn signal flasher relay is located next to the VR and starter solenoid.
 

·
Registered
Joined
·
41 Posts
My '79 CX500 has got the turn relay in the headlight bucket. And the 7V regulator has 3 wires green/black/yellow - non of them removable.
 

·
Registered
Joined
·
38 Posts
Discussion Starter · #13 ·
Your last photo appears to be the 7v regulator. The signal relay should be located near the battery and starter solenoid.
I noticed on the diagram that the 7v regulator has 3 connections, there are only 2 connections for the relay in my last pic.
 

·
Registered
Joined
·
38 Posts
Discussion Starter · #14 ·
...it looks like the turn relay to me. but usually as nolimitz sez, it's not in bucket.... Grey wire supports this given wiring diagram ... yes, Black wire need be connected.

Brown is only used for tailight and parking lamp in headlight.... That cutoff one is for the unused forward parking bulb in headlamp. Usually it's an empty connector on north american models- someone has chopped it off.
Look at my signature. It may help.
Trundler, awesome diagrams!! I am going to use them and look over everything again.

Appreciate all the help from everyone, keep it coming!
 

·
Registered
Joined
·
38 Posts
Discussion Starter · #16 ·
Success!!!!! I'm on top of the world right now, fellas!! I tempararly mocked everything up and connected all wires, some with wire connectors for now. It was a very happy moment when I turned that key for the first time in 6 months and seen those light turn on.



I ended up not connecting the 2 black wires to anything. Looking at the '78 diagram, I noticed that one section just ends with nothing connected to it. And then I am assuming the other black wires connects to the flasher relay.




I was never able to locate the 7V Regulator. Is this a vital part of the system? Should I be able to get lights without it? I don't have any other extra cables.
 

·
Registered
Joined
·
787 Posts
The 7v regulator is a very important piece, a it connects to the temp gauge, to warn of an overheat. While some guys don't use a temp gauge, I wouldn't recommend it. Yes, you can have lights without it.
 

·
Registered
Joined
·
38 Posts
Discussion Starter · #19 ·
On '78's, the 7v regulator is incorporated into the speedometer housing, that's why I couldn't find it. Also on 78's, the turn signal relay is in the headlight housing, so the previously debated item is definitely the turn signal relay. I am now positive that one of my extra black wires goes to the turn signal relay. I believe I am good to go on my wiring now. Just have to get the carbs cleaned and fire this baby up!!

Thanks again for everyone's advice and input.
 
1 - 19 of 19 Posts
Top