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Bad Ground or something else?


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Once again I am faced with dreaded electrical issues. After successfully upgrading my fuse box (Thanks Skydoc and GeorgeS) I was feeling confident to tear apart the dash and replace all dash light bulbs and solder CMU (in way over my head with the CMU now) anyway I notice some of the bulbs are very dim and burn for a bit when key is first turn on but then flicker out. I have turned the dimmer knob up and down and although it does affect the bulbs that are lit normal it does not affect the dim lit bulbs.

 

 

I would think if there was a bad ground all the bulbs would be affected, but I am far from knowing electrical issues.

 

On a side note, anyone know of a good soldering person here in WA state? I have CMU out and apart but I am not sure I see any issues. But the battery light jumper wire MOD is not working and the gear indicator will go in and out on occasion. But other than those two issues the digital display works fine.

 

http://i906.photobucket.com/albums/ac264/bobandlou3/Dash_Bulb.jpg

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It is near impossible to tell from a schematic how grounds are shared normally.

 

In the cluster head though it may be possible to accurately guess at them due to the confined area.

 

The 4 dash bulbs & the temp & volt meter appear to share a common ground circuit. The cruise speedometer sensor also appears to be on this ground wire. This sensor is also utilized in the turn signal self canceling circuit. There is also a line going into the tach from this ground wire. Also, the two turn signal indicators and the cruise indicator light are on this common ground.

 

There are three light circuits in the cluster that are independent of this ground, first is the neutral/gear position indicator. This circuit has a ground path that starts at the switch. The reserve pilot light & the High beam also both originate from the reserve lighting module (RSL). The reserve & high beam indicator appear to share a common ground at the the RSL.

 

If the neutral light is involved, it could be the diode pack has issues.

 

If you would post which bulbs are having problems, it will help me narrow down a cause/solution possibly.

 

Also do you have a gear position indicator in the CMU?

 

Gary

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Yes I do have a gear indicator. The signal, Nutual, and all the Blue and White wire seem to be work fine (I think these are the actual dash bulbs) When sitting on bike, on the right side of the dash there is a socket with Blue and Green wires that is the dim lit bulb in the picture. Then I have socket with Yellow and Red w/Yellow stripe not working and finally a Blue with Brown wire socket not working. I assume these are indicators for High beam, Headlamp and cruise. However switching any of these on or off does not activate any of these bulbs.

 

Just a thought but I thought my cruise bulb worked, could it be that the CMU needs to be plugged in to illuminate this bulb? Also since the headlamp is removed would that be why Highbeam bulb is not illuminated? Maybe the only issue I have is the dim lit bulb that could be the Headlamp bulb since I have it unplugged.

 

Sorry if I sound confused, it's becuase I am.

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Yes I do have a gear indicator. The signal, Nutual, and all the Blue and White wire seem to be work fine (I think these are the actual dash bulbs) When sitting on bike, on the right side of the dash there is a socket with Blue and Green wires that is the dim lit bulb in the picture. Then I have socket with Yellow and Red w/Yellow stripe not working and finally a Blue with Brown wire socket not working. I assume these are indicators for High beam, Headlamp and cruise. However switching any of these on or off does not activate any of these bulbs.

 

Just a thought but I thought my cruise bulb worked, could it be that the CMU needs to be plugged in to illuminate this bulb? Also since the headlamp is removed would that be why Highbeam bulb is not illuminated? Maybe the only issue I have is the dim lit bulb that could be the Headlamp bulb since I have it unplugged.

 

Sorry if I sound confused, it's becuase I am.

 

Its ok Bob, ANYTIME i work on my 85 I am confused, so youre not alone.:confused24:

I do have a spare CMU if you would like to borrow to see if that is your issue. It is a used untested unit but if you would like to try it out, let me know.

 

brian

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I also have a spare CMU that might be easier to get to you since you are in US and Brian is in Canada. Not really looking to get rid of it, but will loan it to you to test your system.

 

It will fit in small priority box, shipping time 3 days. It is also untested, but came from a working bike from a reputable seller on ebay.

 

If you are testing the bulbs with only part of the wiring system hooked up, that could be part of the problem. The RLU is going to be hard to predict how it works with some of the wiring not present. The CMU is going to give warnings without the RLU functioning properly.

 

Gary

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Yes I do have a gear indicator. The signal, Nutual, and all the Blue and White wire seem to be work fine (I think these are the actual dash bulbs) When sitting on bike, on the right side of the dash there is a socket with Blue and Green wires that is the dim lit bulb in the picture. Then I have socket with Yellow and Red w/Yellow stripe not working and finally a Blue with Brown wire socket not working. I assume these are indicators for High beam, Headlamp and cruise. However switching any of these on or off does not activate any of these bulbs.

 

Just a thought but I thought my cruise bulb worked, could it be that the CMU needs to be plugged in to illuminate this bulb? Also since the headlamp is removed would that be why Highbeam bulb is not illuminated? Maybe the only issue I have is the dim lit bulb that could be the Headlamp bulb since I have it unplugged.

 

Sorry if I sound confused, it's becuase I am.

 

The Yellow and Red w/Yellow stripe is the high beam indicator.

 

The Blue and Green wire is probably the RLU bulb.

 

1st two are related to the RLU/headlight not plugged in.

 

The Blue with Brown wire socket is probably the Neutral light.

 

This would probably not be related to 1st two, does indicator on dash show all the gears as you cycle through them?

 

If it does, then I would suspect the diode pack is malfunctioning. This is a black item about 1" square and 3/8" thick. It has 5 wires coming out of it hooking up to a 6pin (2x3 layout) connector. Located on left side of frame somewhat ahead of starter solenoid. Check the connectors on it.

Gary

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Thanks for your help, I got all the bulbs worked out but in my novice attempt to fix battery light on the CMU I made things much worse. Now it does not do the cycle test and the gas gauge no longer works AND the darn battery light is still flashing. guess I am looking for a replacement CMU for an '85 VR :depressed:

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Thanks for your help, I got all the bulbs worked out but in my novice attempt to fix battery light on the CMU I made things much worse. Now it does not do the cycle test and the gas gauge no longer works AND the darn battery light is still flashing. guess I am looking for a replacement CMU for an '85 VR :depressed:

 

Did you by any chance put 12v directly to the battery probe wire. :bang head:

 

You don't need to answer. But if you did, you allowed the factory supplied smoke to escape from the CMU.

 

Your assessment that you need a new CMU is very accurate, should the above guess have actually happened.

 

Gary

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No, i never did connect directly to battery without some kind of resister like the MOD talks about. I tried making my own but when it did not turn out the warning light it was suggested to me here on the forums that my CMU could have cracked solder joints. Not knowing how to solder Ii lived with the warning light until I ordered some parts from skydoc, I went ahead and ordered his patch wire for the fix thinkng maybe I screwed up the one I made some how. But when his did not shut the battery light eiher, I had to believe that it ws cracked solder joints on the CMU. So today iI bought soldering iron and tried my hand at soldering it myself and that is how my CMU ended up worse than when I started. Leson of the day is to know your limits or pay big time.

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If you want, send it to me and I can go over the soldering.

 

If you ship it priority, I should get it in three business days, 1 day to check and 3 days shipping back. You pay shipping both ways is all.

 

No sure I can fix it, but I can try. I have done two of them and a couple of TCI's, and a CLASS module and they lived.

 

Gary

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Bob,

 

I helped it a little bit, its not perfect, but the segments are much more uniform than when I started.

 

I reflowed all the solder joints on the top board & some of them on main board. Main board has much smaller gauge connectors and its harder to reflow the solder joints & not bridge them. I cleaned contact surfaces to indicator panel with rubbing alcohol.

 

The battery indicator appears to be fubared though. I couldn't get it to turn off.

 

1st picture is on power up.

 

2nd is after it cycles through. The headlamp indicator is because I have rewired my headlights, it should be OK on yours. A couple of the segments are dimly lit, side stand & brake fluid.

 

3rd picture is of mine for comparison.

 

What you can do to get rid of the flashing red indicator on left side due to battery indicator, is to put a little black paint over it.

 

Gary

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