Blowing Tach fuses

[greggh]

I have a 1998 Standard that has just surpassed 60K while ridding yesterday I have replaced the fuse for the Tach twice.
Coming to Work this morning all was fine until I got to Work and the darn thing blows out again.
Any Ideas would greatly be appreciated.
Gregg

[Mr.BubblesVRCCDS0008]

Tach fuse also is wired into tailight circuit. Start looking at lights problem may be in them. 

[chrise2469]

Check your rear tire wiring harness for fraying or an exposed wire in your brake light cluster.  The tach is grounded through the brakes.  After that check main battery ground to frame connection.

[fudgie]

Check the harness under the rear fender for a kink. Esp if you had the rear fender off within a few years.

[greggh]

Lunch Time here in Omaha.
Replaced the fuse and it works until the next time it blows.
I have repeatedly pumped the rear brake to see if that would replicate the problem, it did not.
I have had the rear fender apart in the past -  about 1 1/2 to 2 years ago.  I do not think I have pinched any wires during re-assembly I am 100% positive I did not pinch any wires.  Albeit I will double check to ensure that is not the problem.

The Cobra Light bar must be connected some were inline to the fuse because I loose the Cobra lights as well.
I hate wiring gremlins 
I will have to check later this week because working to Jobs leaves me little time to chase down the problem.

TIA Gregg

[Ricky-D]

I'd suspect it is the Cobra Light Bar that is causing the problem since the Honda electrics are very substantial and well protected.

Why not disconnect the light bar for a while and see if the same fuse blowing happens again.

You have to remove all possibilities anyway so that would be a good place to start!

***

[greggh]

Great idea RickyD
I will post my findings after a substantial test.

Gregg

[R J]

If you do disconnect the Cobra's and that cures the problem, rewire the Cobra's properly with a relay in a new, Cobra Lightbar ONLY circuit.    It will cause you to turn them off manually, and before ya hit the starter when starting.

If ya get over to Panora, and North about 4 miles on Hwy to the big barn, Craig can probably fix ya up to make them go out when ya hit the starter.   If not, come on down to Des Moines and I know my son can do it.  He did mine, we replaced this little red conector.



Used this replacement for an  older Gold Wing.  In the replacement connector, ya have to move the Big red  wire into the hole that matches on the bike side of it.

[greggh]

I have done nothing yet but I do know that the on/off switch for the Cobras is not working properly and would prefer too just runthem hot all the time.
Currently they are wired with the head light and have been like that since I have owned it, 4 years now.
The ride to Des Moines would be a nice ride.  Not sure what my schedual looks like yet but will keep it in mind for sure.
Thanks RJ

Still going to disconnect the cobras first and see how that pans out.

Gregg

[Robert]

May be nothing wrong with the wiring you may just have to much on that circuit. A 10 amp fuse is pretty small to run all of that with a light bar. I bet with the bike running if you put your turn signals on and have everything else on for awhile you can get it to blow. I'm with RJ on this one.

[Valkpilot]

May be nothing wrong with the wiring you may just have to much on that circuit. A 10 amp fuse is pretty small to run all of that with a light bar. I bet with the bike running if you put your turn signals on and have everything else on for awhile you can get it to blow. I'm with RJ on this one.

This is a good possibility.  If the Cobra light bar has 35 watt bulbs, it is adding a 6 amp draw to the circuit.  Amps = watts/volts.  2 x 35W = 70W.  70W/12V = 5.8 amps

Why didn't it blow before?  The circuit could have been borderline all along and something has changed.  Maybe a little extra corrosion on a connection or in a wire.  It would be hard to figure out unless you can find something obvious, like a cut in the wire insulation that let in water and caused some corrosion buildup.

The light bar should  be on its own fused circuit, run through a relay that is triggered by the starter switch circuit so that the lights go off when you press the starter button.  This keeps the light bar amperage off other circuits and keeps you from burning up your starter button.  There are diagrams on how to do this here: http://www.rattlebars.com/valkfaq/circuits.html

[Garland]

I was having trouble with my Cobras blowing fuses. Turned out to be one of the brass tab that the wires connect to on the back of one bulb was too close the the chrome shell. It was shorting out when going over bumps. Bent it down, no more problem. Hope yours is as simple a fix...

[greggh]

Well after a few blown fuses it has been determined that the Cobra Light Bar is the Culprit.
I am having success with turning the lights off and no more blown fuse.
Turn the switch on and the fuse goes.
I have replaced the relay and still blows.
Not sure if the switch has a short or what.
Ran out of time tonight and work both jobs on Thursday so I will just run with the headlight only for now.

RJ coming to Des Moines sounds more and more inviting, you are aware that the Loess Hills Rally is this weekend right.  Not sure if I will be involved in that or not.

I do have a friend that knows more about wiring than I do, so it is possible that he may intervene.
I will let you know more later.
Thanks to all for you help.  The link to Chets Circuits was informative, it gave me a head ach though.

[R J]

Greg, wasn't aware of the Hills Rally.

Send me the rides in your area and I'll let all the Iowa riders know of them..

If ya don't have my email addy anymore  here it is again/

rjb448AThotmailDOTcom.

I think you can figure that out from the way it is written.

[greggh]

RJ,  The Loess Hills Rally is an Iowa Rally happens every fall in the Loess Hills area.
I got the email figured out.
I will contact you later