Topic: CB550 warning lights, should they be on with the key On?

[j squared]

First off, the bike is a '74 CB550. I started buttoning up the wiring in my headlight bucket last night, and despite my carefully taken notes and available wiring diagrams some of the things I saw in there were questionable.  So, I got everything connected as I saw fit and connected my battery for some electrical tests.

One thing I noticed was that my warning lights (Oil, High beam, etc) were not lit when i turned the key to either position from off. I was expecting the Oil light to be lit in this case, am i wrong in that assumption?  I tested the headlight on both settings and it lit up as I expected (and the On/Off headlight switch worked fine) but the high beam indicator light didnt light up at the same time.

Now, the bike was not running at the time, just had battery power and key On.  Are the warning lights supposed to work when the motor is not running?  I cant test the turn signals as they are not connected yet.  The neutral light wasnt lit, but I know thats a common issue so i didnt think twice about it.  Im wondering if I might have some wires connected wrong in the headlight bucket, although the horn and headlight switches are operating properly so it must be the warning lights only.

And another side question:  with connectors that have 4 ports (Look like a sideways H, four wires into one connector) does the connector share continuity among all connected wires equally?  What I mean is, if four wires are going into one connector does it matter which wires are across from each other? I assumed the connection would be live across all four wires equally so I didnt really pay much attention to that, but should I have??

Thanks in advance everyone. Glad to be posting technical questions on this project, it means Im making progress

[MacGyver]

I do know the status lights on my 75 550 work with and without the motor running.  My best advice would be to print out a copy of your wiring harness, get a highlighter and a cheap multimeter, and test out the circuit running to the assembly.  As far as the H harness I am not sure.  If you post a picture I could tell you.

[jimbir]

with connectors that have 4 ports (Look like a sideways H, four wires into one connector) does the connector share continuity among all connected wires equally?

Yes. Those sockets are a convenient means of connecting 3 or 4 wires together. Sorta like twisting them together and putting a wire nut on them.

[j squared]

Ok thats what I was hoping for   Its weird though, so for the high beam connector there are three wires: one coming from the switch, one to the indicator light, and one to the headlight itself.  If the switch provides power to the connector and in turn switches the high-beam on, I would think it would also be able to turn the indicator on as well.  This has me worried that I have an issue with some type of main ground to the indicator lights themselves, which would make them all not work. 

taking a closer look at the diagram the oil warning light looks to be dependent upon the emergency switch being set to On and Im not sure I had it on when i ran the test.  Will have to take a second look when i get home.

Thanks for the help so far, yall.

[Mavryk03]

I have a 75 CB550F and when turning to key to the on postion or auxiliary power my red and amber light come. So red is oil and what ever the amber light is turn singal i think hope that helps sounds like you just got some wires crossed

[j squared]

Do you remember offhand if the lights come on with the emergency switch Off, or only when it is set to Run?

[flybox1]

Do you remember offhand if the lights come on with the emergency switch Off, or only when it is set to Run?

the shoud come on with OFF or RUN and key turned.
on my 350F, only the RED oil light is illuminated whenthe key is turned (and neutral if bike is in neutral)
amber only comes on when signals are engaged.

[j squared]

Well shoot, looks like I have some work ahead of me :/

[jimbir]

so for the high beam connector there are three wires: one coming from the switch, one to the indicator light, and one to the headlight itself.  If the switch provides power to the connector and in turn switches the high-beam on, I would think it would also be able to turn the indicator on as well.

On my '76 CB550F There are five lights on the instrument panel. Red-oil press indicator, on with key on, off when engine running. Green-neutral indicator, on when in neutral, off when in gear. Blue-high beam indicator. Right and left amber turn signal indicators. Whether The kill switch on the right hand grip is on or off has no effect on the operation of the lights. The ignition switch has a "p" position. When the key is in this position, all lights are off except the tail light. You need to be very careful to follow the wiring diagram exactly. I will send the one I used to your email address.

[j squared]

That would be awesome, thanks man!  Send it to jhenline at gmail dot com please

I have a '74 with only the 4 lights (Oil, Neutral, High Beam, Turn) but Im pretty sure operation is the same between both.  I will double check the key position and some voltage to and from the wiring for the indicators and oil sending unit and post back.  Thanks again!!

[Duanob]

Funny I've had my bucket open at least 15 times in the past week trying to get everything hooked up right and working.

First before chasing down electrical problems start with the bulbs make sure they all work.

Second check your oil temp sensing unit under the sprocket cover. They are is usually corroded and rusty so make sure the contact is clean. The oil light should be on when the key is turned on until pressure turns it off.

Third your high beam idiot light should be on if the high beam is on when the key is turned on. What I know about the headlight wiring is you have a hot white wire and a blue wire one for low and one for high that come from the left switch. You will also have a green and a black ground/ neutral wires. I also have a black /w Yellow wire that runs power to the left hand switch. This wasn't in my 1976 schematic but I hooked it up to a brown power lead that isn't hooked to anything in the bucket and I got everything to work properly. Not sure if my left bar switch is original, probably not but it works. I even got my turn flasher idiot light to work but I don't have all the corner flashers working yet. I just happy to have it wired enough to start it.

[j squared]

Small update, I do have the high beam light working fine, must have just been in a rush and pushed the key one position too far when I checked it. Still no oil or neutral lights.  I have spark when I run the kick start so Im thinking my main chassis ground is good, must be somewhere in the wiring I did.

I noticed in the wiring diagram that both of these lights (oil and neutral) use a common ground circuit, a set of black wires running through a connector in the headlight bucket.  I'm guessing I connected this up wrong.  Looked last night for a second and noticed there are two 4-wire connectors of all black wiring, maybe I mixed up which goes to which?  Im going to take a closer look this weekend, maybe start the bucket wiring from scratch.  I remember when I got the bike both lights were operational so I can only assume I fudged something up to make them not work. 

Can I test the lights by running power to the non-black wire for these two bulbs?  Oil is blue/red and neutral is green/red I believe, with a black wire going to each bulb also.  If I give 12v to the non-black side of each should the lights illuminate?

Funny I've had my bucket open at least 15 times in the past week trying to get everything hooked up right and working.

First before chasing down electrical problems start with the bulbs make sure they all work.

Second check your oil temp sensing unit under the sprocket cover. They are is usually corroded and rusty so make sure the contact is clean. The oil light should be on when the key is turned on until pressure turns it off.

Third your high beam idiot light should be on if the high beam is on when the key is turned on. What I know about the headlight wiring is you have a hot white wire and a blue wire one for low and one for high that come from the left switch. You will also have a green and a black ground/ neutral wires. I also have a black /w Yellow wire that runs power to the left hand switch. This wasn't in my 1976 schematic but I hooked it up to a brown power lead that isn't hooked to anything in the bucket and I got everything to work properly. Not sure if my left bar switch is original, probably not but it works. I even got my turn flasher idiot light to work but I don't have all the corner flashers working yet. I just happy to have it wired enough to start it.

I was really wondering about that brown lead I didnt have connected up At least thats one thing down haha.

[j squared]

Found this thread in my searching:  http://forums.sohc4.net/index.php?topic=53213.0

Guess I was thinking about the circuit backwards, with the black wires being 12v and the colored wires acting as grounds at the sensors.  Makes sense, seeing as how the other side of the sensors are grounded to the chassis, the sensors just complete the grounds to turn on the lights.  Too simple

Imma go through the tests mentioned there when I get home, should be able to track it down now I think.

[Duanob]

It helps to have a wire connected directly to your battery as a hot lead to test your lights. If they don't work then your bulbs are burnt. If they do work then you have a loose wire or a short somewhere. Also a voltage meter helps a lot as well. Your black and your greens are all grounded. Not sure why they used 2 colors but I'm sure Honda had its reasons.

[j squared]

A few threads I just read (link above) say the black wires in multi-connectors in the headlight bucket are power leads and should have switched 12v+. Are you sure they are grounds?

[cobra2411]

Green is usually ground on these bikes (at least the 750's).

Warning lights on my come on when the key is on. Red for oil always, green for neutral - if in neutral, Orange for the signals if on, and red for the high beams if selected.

[Duanob]

A few threads I just read (link above) say the black wires in multi-connectors in the headlight bucket are power leads and should have switched 12v+. Are you sure they are grounds?

Pretty sure mine are grounded. I never got voltage between the green and black wires. Black wires accompany colored wires to ungrounded items on the bike, according to the schematic. You're not woring from a wiring diagram? Here you go.

[j squared]

Yep, have been working from a wiring diagram, just not used to older electronics like this. Had the function of the sensors mixed up  That one looks waaaaay easier to read than the ones I have though, thanks.

At any rate, I think I found the issues.

Oil light:  I grounded the bulb directly in the headlight bucket connector and it came lit up, so I pulled the sprocket cover and grounded it directly at the sensor.  Light comes on from that, so I guess either the sensor is crudded up and needs a cleaning or its gone bad.  Ill clean it up and see what happens, but I can at least say its not the wiring at this point.  Good news.

Neutral light:  Grounded the bulb directly like I did for the oil light and it did not light up.  So connected the oil light wire (which I know works) to the neutral bulb and it still didnt light up when i grounded the oil sensor.  So, looks like the bulb is out .


Bad news is I got a big mess of nasty oil from behind the sprocket cover when I pulled it.  Hoping its just a bad gasket and not a worn-through engine cover or something bad like that.  Was on my lunch break so I couldnt really delve into it, but once I clean it up some I will take a look.

Thanks for the help everyone, I really appreciate it.

[j squared]

Id rather not start a new thread, but wanted to see if anyone could offer some insight on my testing of the oil sensor so far.

First things first, I disconnected the wire from the top of the oil sensor and touched it to the engine case and the oil light illuminated, so Im sure the wiring from the sensor to the warning light is good.

Afterwards I removed the sensor and set my multimeter to Ohms.  With the sensor removed from the bike I touched one lead to the top where the wire connects and the other to the threaded section of the sensor.  The impedance reading went to infinity. it is my understanding that this should occur when the sensor is seeing proper oil pressure, and without it doing this test should show little or no impedance between these two points.  So, does this tell me the sensor is bad ("stuck" in the closed state)?

Finally, Ive read on here about picking up a generic sensor from the auto parts store, is this feasible?  Im a bit concerned about the thread differences, the CB sensor being BSPT and most vehicle sensors being NPT. I am sure I could get a sensor online or from the stealership, but for the sake of time and cost is an auto parts store replacement an OK option?

Thanks in advance for any help!! Glad to have this (mostly) figured out

[Ms Tokyo]

I’ve updated to LED in the indicator panel. I am having no luck getting the oil pressure or neutral indicators to light. I have pulled the wiring and tested for continuity. Not an issue. I have cleaned the corrosion out of the light socket itself for good grounding. Since these two lights share a common power lead and I am now running LED, do I need to separate into individual power leads? I’ve tested directly from the battery with the individual light wiring grounded, no luck. Bike is a 76 CB550k

Thanks!