Topic: Oil and Neutral lights flickering between key positions

[Scott S]

 I asked about this in my project thread but wanted to get some more info.
 1971 CB500, just installed a new battery and put power to it for the first time in about 30 years.

I *THOUGHT* that the oil and neutral idiot lights didn't work and planned on pulling the sprocket cover to check. But... then I was cycling the key switch last night when it was dim in the garage and saw them flash, but only when I'm in between detents on the key switch.
  What would cause the oil and neutral idiot lights to flash when I'm in between detents on the key switch but not stay illuminated when the key is in the RUN position? They also flash briefly when going from RUN to the PARK position on the switch.

 I sprayed contact cleaner in the ignition switch and checked the connection at the plug. I have NOT pulled the sprocket cover to check the switches, but if they're flickering between detent positions, that means the circuit is probably good, right?

[newday777]

Where you have sprayed the switch and it didn't fix it, you will either need to open up the bottom of the switch and clean/adjust/fill(solder) the contacts. Or replace the switch..

[BenelliSEI]

The neutral and oil switches feed a ground (-) to the lamp. The lamps should have a feed (+) that is permanently there when the ignition is ON. Check your wiring diagram for your bike. Could be a loose connector in the headlight bucket, loose fuse connection, or a bad ground to your engine. But from your description, most likely the ignition switch falling apart internally. Get a new one....

[BenelliSEI]

Just reread your post and caught the “first time in 30 years” part. Try hooking a test light to your power lead to the coils. Does it flicker the same way as you run the key ON and OFF? If so, I’s say faulty/ dirty switch (key) contacts.....

[Scott S]

 The switch has been extended, as the bike came with a Windjammer fairing. I already have two keys; the easy answer might be to just replace the switch.

[MauiK3]

and the connector the switch connects with

[MauiK3]

left out "and check"

[Scott S]

and the connector the switch connects with

 I did. I cleaned and checked it when I checked the switch. Nothing obvious there.

[newday777]

The switch has been extended, as the bike came with a Windjammer fairing. I already have two keys; the easy answer might be to just replace the switch.

Then you need to inspect the extension wire joints.
Honda usually sells an ignition switch, seat latch and steering lock set keyed alike.

[Scott S]

 Well, new ignition switch and it's doing the same thing. Guess I'll have to dig a little deeper....pull the sprocket cover and look in the headlight bucket.

[bryanj]

Try the fuse, just cos it looks good they can detach from end cap inside

[Scott S]

Try the fuse, just cos it looks good they can detach from end cap inside

 It's an early '71 CB500. Only one fuse. If everything else on the bike works as it should, could the fuse still be causing this?
 If so, how?

[bryanj]

If not that, and yes it could, it has to be a bad connector where the blacks are joined, possibly even in the loom

[BenelliSEI]

If it happens with a new switch too, there is a wire crossed over somewhere. As you break the connection, you’re getting in instant of open circuit and working lights. Get out your wiring diagram and start tracing wires one by one….. There’s a dead short spot somewhere.

[grcamna2]

Color to color and check the Ground - connections going from the harness to the frame.

[Scott S]

 Checked and cleaned fuse.
 Checked all black wires and grounds in headlight bucket.
 I cleaned and checked the engine ground.

 Still doing the same thing. I'll pull the sprocket cover when I get the gumption to actually do it.

 I ought to set the points/timing and put some gas in it and see if it runs! Warm weather is coming, so ....soon.

[grcamna2]

I look forward to what you find on the two wires under the sprocket cover.

[Scott S]

I look forward to what you find on the two wires under the sprocket cover.

 Everything was as it should be.
 Without ripping any wire coverings off, I looked around and didn't see anything obvious.
 Maybe I'll just live with it.....see what happens when the bike is actually running.


 One thing I haven't mentioned yet: the dash bulbs are LED, but I've used them before and never had an issue like this.

[BenelliSEI]

Scott….. just check at the lamps with a test lamp. You should be able to determine if your are missing power or ground. If you have both, replace those lamps.

[grcamna2]

Scott….. just check at the lamps with a test lamp. You should be able to determine if your are missing power or ground. If you have both, replace those lamps.

 

[newday777]

I look forward to what you find on the two wires under the sprocket cover.

 Everything was as it should be.
 Without ripping any wire coverings off, I looked around and didn't see anything obvious.
 Maybe I'll just live with it.....see what happens when the bike is actually running.


 One thing I haven't mentioned yet: the dash bulbs are LED, but I've used them before and never had an issue like this.

Important information left out on your part.......
The LEDs on the oil and neutral have been known to cause problems. Put the incandescent bulbs back in to see....

[Scott S]

 I knew I couldn't use it in the turn signal, but I've used them in all of the other idiot lights before. I'll try swapping them out.

[Scott S]

 Well, the incandescent bulbs worked. I even tried flipping the LED bulbs to make sure the polarity was correct.

 I've used LED's in the idiot lights before and didn't have any issues.. in fact,, the Hi beam indicator on this bike still is an LED.
 Wonder why the O and N lights didn't work with them? Cheap LED's?

[Don R]

 LED's use very little power, a weak ground can cause a problem while a standard bulb pulls enough wattage to feed across a weak connection.
   An old Goldwing trick is to wire a bigger bulb in series with the N light, that increases the load enough to make the poor ground in a carboned-up switch operate. Some guys hide it in a fairing, other guys leave it in plain sight.

[BenelliSEI]

Solved! Well done.