Voltage Regulator Question
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Novice
Joined: Sep 2012
Posts: 22
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From: Pittsburgh, PA
Voltage Regulator Question
I have a 1995 Ultra Classic. When i turn on my accessory brake lites, spots, radio etc. i see the volt gauge on dash drop from like 13-14 volts down to apx 8-10 volts. This is most noticable at low idle 1000rpm (eg. at a red lite). The result is the radio (and amp/cb module that powers rear speakers) cuts out when i apply the brakes. I can see the guage go down to like 8 volts. The bike has a brand new battery and the hd dealer checked the stator output and said it was good. They checked the voltage reg. WITHOUT any xtra electrical items on and said it was good. Could this problem be caused by an old voltage reg thats not performing as it should anymore? It could be the original from 1995. Any advice would be greatly appreciated. THX
Road Master
Joined: Oct 2011
Posts: 957
Likes: 2
From: Carlsbad Springs Ontario
If the problem began after you got a new battery , its the battery or connections.
If you replaced the battery to solve the problem , check the charging voltage at 1500-2000 rpm. it should be approx. 13-14 volts .
If you replaced the battery to solve the problem , check the charging voltage at 1500-2000 rpm. it should be approx. 13-14 volts .
Grand HDF Member
Joined: May 2008
Posts: 4,326
Likes: 3,614
From: Picayune, Ms.
Look for a short in the brake lite system. Appears the brake lite circuit is drawing more voltage than necessary.
You could isolate this by removing the light bulbs to create an open circuit, when you find the one that when removed doesn't draw down the voltage, check that circuit.
IE: Remove the stop lite bulb. Now pull the front break lever. Let's say the voltage remains normal when you do that. Now release the front lever and press the rear break foot peg, if the voltage then takes a drop there is something shorted in the rear foot brake system. With no bulb there should be no voltage drop.
Look for extra wiring that someone may have added something like a "Back-off" feature item, and then removed the unit but didn't secure the wiring.
Good luck finding the short, usually the voltage regulator like all things electronic either works or is dead, sometimes temperature has an effect, but other than that I would say if it tested OK then it probably is.
Expensive and non-returnable item.
You could isolate this by removing the light bulbs to create an open circuit, when you find the one that when removed doesn't draw down the voltage, check that circuit.
IE: Remove the stop lite bulb. Now pull the front break lever. Let's say the voltage remains normal when you do that. Now release the front lever and press the rear break foot peg, if the voltage then takes a drop there is something shorted in the rear foot brake system. With no bulb there should be no voltage drop.
Look for extra wiring that someone may have added something like a "Back-off" feature item, and then removed the unit but didn't secure the wiring.
Good luck finding the short, usually the voltage regulator like all things electronic either works or is dead, sometimes temperature has an effect, but other than that I would say if it tested OK then it probably is.
Expensive and non-returnable item.
Road Master
Joined: Oct 2011
Posts: 957
Likes: 2
From: Carlsbad Springs Ontario
To help find a short to ground ...
Remove all key off loads such as radio memory , efi computer if fuel injected , etc.
When your sure there are no loads on the battery with key off , disconnect the neg . battery cable and connect a 12V. test light or dc 12v voltage meter in series between the battery neg. post and neg. battery cable . Remove any lamp bulbs that operate when key is off. Now turn key on and apply brakes . If test lamp lights up with brake peddle or hand lever , the short to ground is in either of these systems , turn the bars full left and right when checking brake lever and sit hard on the seat , give the bike a few hard raps here and there to check for intermittant shorts .
Finding wiring shorts can be a bitch , hope Kabear and i and some luck does it for you.
Remove all key off loads such as radio memory , efi computer if fuel injected , etc.
When your sure there are no loads on the battery with key off , disconnect the neg . battery cable and connect a 12V. test light or dc 12v voltage meter in series between the battery neg. post and neg. battery cable . Remove any lamp bulbs that operate when key is off. Now turn key on and apply brakes . If test lamp lights up with brake peddle or hand lever , the short to ground is in either of these systems , turn the bars full left and right when checking brake lever and sit hard on the seat , give the bike a few hard raps here and there to check for intermittant shorts .
Finding wiring shorts can be a bitch , hope Kabear and i and some luck does it for you.
Dirt don't hurt
Joined: Jan 2011
Posts: 21,065
Likes: 4,561
From: Haslet Texas
Do the simple and easy things first.
Even though you have a new battery take it to an auto parts store and have them put it on a load tester. It is rare but you could have gotten a bad battery.
Next (if the battery tests good) start the bike and put a volt meter across the posts and verify that your dash volt meter is accurate.
After you do those two things then start on your wiring harness as stated above.
Even though you have a new battery take it to an auto parts store and have them put it on a load tester. It is rare but you could have gotten a bad battery.
Next (if the battery tests good) start the bike and put a volt meter across the posts and verify that your dash volt meter is accurate.
After you do those two things then start on your wiring harness as stated above.
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