Harley Davidson V-Rod Forum banner

1 - 20 of 35 Posts

·
Registered
Joined
·
263 Posts
Discussion Starter · #1 ·
Hey all, I blew the small 15 amp fuse marked "Battery" and there was no odometer and the tack, speedo and gas gauge were all stuck at like 3000 rpm, 30 mph and say 1/2 full ?? with the ignition switch off or on. Bike started fine and everything else seemed to work.
Couldn't figure out why it blew, so put in a new fuse and everything went back to normal. Went riding and after a while it blew again.
I figured out that the radiator fans are on this fuse too. (sound right ?) and it doesn't blow when the fans come on.....it blows when they shut off !! ???
Anybody out there have any ideas of what might be going on?? And what to test or check?? This electrical stuff is black magic sometimes, so any help would be most appreciated, thanks in advance all you electrical whizzes,
humbly, V-Rodney :banghead:
 

·
Color me Gone
Joined
·
27,333 Posts
Sounds like you may have a bad fan motor or I should say the fan motors have been known to cause problems and blow that fuse.
 

·
Premium Member
Joined
·
1,501 Posts
Look at the bottom of the bike on the right side below the gas tank. There is a brake light switch in series with the rear brake like. The 12 vdc spade lug has a rubber boot that is contacting your frame when you hit a bump.
 

·
Friend of Max.
Joined
·
21,719 Posts
Panman said:
Look at the bottom of the bike on the right side below the gas tank. There is a brake light switch in series with the rear brake like. The 12 vdc spade lug has a rubber boot that is contacting your frame when you hit a bump.
Panman, that would cause the Accessory fuse to blow.
 

·
Premium Member
Joined
·
1,501 Posts
rjrivero said:
Panman, that would cause the Accessory fuse to blow.
I didn't look at a wiring diagram but it sounded like the same thing that happened to Firemedic last year and thought it was worth checking.

It takes a while for the contact to wear through the boot and if that is the problem it is a easy fix.
 

·
Color me Gone
Joined
·
27,333 Posts
RJ is correct that won't blow the battery fuse but your right that there have been reports of the rear stop light switch wires rubbing the back of the engine also. If the fans or one of the fan motors is bad if you have a dvm you can check the draw of them, if you don't you can replace the fuse, disconnect one motor at a time and let the bike idle until the fans come on. If it blows the fuse you know you have the bad motor, if the motor runs you know it is the other motor or not them at all. There have been several reports of the motors causing this fuse to blow and having to ride the bike until it gets warm points to the fan motors. Usually shorts don't come and go or you can associate them to hitting a bump or leaning one way. There really isn't any rocket science involved in finding them.
 

·
2" of dangling death
Joined
·
10,933 Posts
I have to agree with max, sounds like a fan is out. this was a problem on a bike i worked on last winter and it was a fan
 

·
Registered
Joined
·
263 Posts
Discussion Starter · #8 ·
Hey Max and Tyson,

I think you guys are right so I'm jumping in and pulling them out. Thank goodness I have a spare pair of fans on hand. Just hope I can re-use those funky retainers..............Thanks for your help. V-Rodney
 

·
2" of dangling death
Joined
·
10,933 Posts
Danno has a post on this somewhere, he had the same problem
 

·
2" of dangling death
Joined
·
10,933 Posts

·
Riding the good life
Joined
·
4,908 Posts
Before you pull the fans, how old is your battery?

I had the same stuff happening to me and the battery was on its last legs. RJ advise "itsda fans, itsda fans" but it was not.

From what I read if the fans are on their way out, they bind when the spin causing the draw on the current to go over what is required to turn them on. That draw blows the 10 amp fuse.

Checking how loose/tight the fans were on a new VR at the dealerhsip on the floor matched the same feel of the fans on my 02. Feels like tiny speed bumps as the fan turns, and if you free wheel it without the juice on they will spin about 1.5 revolutions with a quick kick on the blades with a finger.

What actually was happening is the battery was loosing the capaicty to hold a strong charge to run all the systems the bike needs to operate on, causing a surge to occur as the draw requires more than the fuse can handle. The system amps it up but nothing is there to allow the surge to taper and flow through the battery as the plates are wimping out, thus allowing the load to by pass into the system.

I did not reads this anywhere, but presumed that this was the case as the battery was the original from 02, and this was going on if I remeber right back in April.

So I had almost 5 years road time with the battery and I know that it needed to be replaced cause folks had been posting they are getting 2 maybe 3 years in most cases with their batterys in climates where 4 seasons causes batteries more grief. Since Hawaii does not get dramatic drops in temps, I believe thats why I was able to get the extra years.

I might be wrong in this, but it is worth a check to see what happens with your battery when a load test is done.

Nothing like pulling the fans out and then to find you have to do the battery.

BTW, I have put on about 3,000 miles since then, no blown fuses and the fans do what they are supposed to do.
 

·
Premium Member
Joined
·
1,501 Posts
I just replaced my five year old battery yesterday and before I did I had an incident when the fans came on and it missed a beat. I thought it was odd and knew it must have been a voltage drop but no blown fuse. The current handling capacity had diminished to the point I was afraid I would get stranded. I find it hard to understand what would cause a surge when they turn off.

If you unplug the fans one at a time to trouble shoot chances are you will change the load enough that neither of them will cause the fuse to blow even if they are the problem. Another possibility is that there is a relay that turns the fans on/off that has some resistance that causes them to draw higher current. Also if the fuse blows it would make the fans go off so going off is not what is causing the fuse to blow.
 

·
Color me Gone
Joined
·
27,333 Posts
Rodney test your fan motors, there is a very high probability that you have a bad motor. I have no way to even try to explain low battery causing fuses to blow. High amperage draw is what blows fuses.
 

·
Premium Member
Joined
·
1,501 Posts
Max said:
Rodney test your fan motors, there is a very high probability that you have a bad motor. I have no way to even try to explain low battery causing fuses to blow. High amperage draw is what blows fuses.
Just for fun I thought I would post this;

Power in Watts is the total of voltage times current. E X I = W. Where E is in (volts), I in (amps), & P in (watts).

The fans will draw the same power but when the battery voltage drops, (due to a surge in current when the fans come on) the current will go up to deliver the same amount of power.

It would still most likely be a fan motor drawing higher than normal current but explains why low battery voltage would compound the problem.

We used muffin fans on electronic equipment racks and designed a window detector to measure the current and create an alarm when a fan failed. The design was based on the fan specification and we had to open up the detection voltage about four times the calculated value because good fans required such a different amount of current depending on which supplier we bought from.

Another alternative is just put a 20 amp fuse in and see what happens. If it doesn’t blow the fan may just draw a slight amount more current than the design intended.
 

·
Greg/Moderator
Joined
·
18,951 Posts
My fan was seized and killed the same fuse, give the fans a turn and I think you'll find the culprit.
 

·
Registered
Joined
·
1,980 Posts
Max said:
Rodney test your fan motors, there is a very high probability that you have a bad motor. I have no way to even try to explain low battery causing fuses to blow. High amperage draw is what blows fuses.
I always thought "Gay Electrons" Blew a Fuse :spank:
 

·
Premium Member
Joined
·
11,364 Posts
Panman said:
Just for fun I thought I would post this;

Power in Watts is the total of voltage times current. E X I = W. Where E is in (volts), I in (amps), & P in (watts).

The fans will draw the same power but when the battery voltage drops, (due to a surge in current when the fans come on) the current will go up to deliver the same amount of power.

It would still most likely be a fan motor drawing higher than normal current but explains why low battery voltage would compound the problem.

We used muffin fans on electronic equipment racks and designed a window detector to measure the current and create an alarm when a fan failed. The design was based on the fan specification and we had to open up the detection voltage about four times the calculated value because good fans required such a different amount of current depending on which supplier we bought from.

Another alternative is just put a 20 amp fuse in and see what happens. If it doesn’t blow the fan may just draw a slight amount more current than the design intended.
Bad Idea. Burnt up wire harness could happen.
 

·
Color me Gone
Joined
·
27,333 Posts
RustyG said:
Bad Idea. Burnt up wire harness could happen.
I agree, never us a larger fuse then what was installed from the factory. You could turn a small probem into a major problem. I remember a guy that had a penny in a cigerette lighter and stuck a circuit breaker into a fuse slot and torched the dash and dash harness on a camero. It turned a small problem into major expense and problem.
 

·
Premium Member
Joined
·
1,501 Posts
All wiring is over engineered, I agree to remove a fuse would be a bad idea but a 5 amps increase in a fuse rating is not going to cause any problems. You will find a number of recalls where that is the exact solution.

I have been an electrical engineer for 25 years and would not suggest it if it were a bad idea.
 
1 - 20 of 35 Posts
Top