Ignition fuse blowing

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Jul 10, 2019 | 01:17 PM

EVOrider

Thread Starter

Stellar HDF Member

Joined: Feb 2007

Posts: 2,558

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From: Russellville, Arkansas

Ignition fuse blowing

My 1998 FLHTCUI has developed a problem. It was running just fine down the interstate. Pulled up to gas pump and still idling....the bike just died. Could not hear the fuel pump whine. Mileage.....100,000 miles

I immediately checked the run/off switch.

Checked the two connections under fuel tank canopy that run to the fuel pump...they were fine. They are known to lose connection.

I swapped the relays around....no luck

The ignition 15 amp fuse was blown. Put in another and it blew as well.

Loosened up and removed the switch housing....all seemed good. I was thinking a pinched wire in there.

Removed the outer fairing....I didn’t see anything out of place.

After bike cooled off....it fired right up....still towed it home because I didn’t trust it.

I turned handlebars left and right while bike was running....no problem.

Bike has cooled off for two hours.....it blows the fuse as soon as I turn the ignition to on.

Now it just blows reguardless.....hot or cold.

The cam position sensor is original.....
The coil is original.....
Fuel pump is original.....fuse never blew

I have the shop book, breakout box, and a scanalyzer.

Any help to guide me would be helpful. I am at a loss on this one. I don’t want to start replacing parts until I know it failed and what caused it to fail. Of course....any recommendations to replace a part due due to age and mileage?

Thanks again

Jul 10, 2019 | 03:26 PM

Dan89FLSTC

Seasoned HDF Member

Joined: May 2008

Posts: 21,029

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From: South Carolina

This should be fairly straight forward, since the fuse blows as soon as the switch is turned on...

The ignition circuit passes through 4 harnesses.

Main Harness
Interconnect Harness
Right Hand Switch (Kill Switch)
Ignition Harness

Disconnect the harnesses, one at a time, starting furthest harness away from the fuse.

Disconnect the ignition harness first, by unplugging connector 8A/B. Put in fuse, turn on ignition, see if fuse blows.

Follow with the connector for the Right Hand Switches, connector 22 A/B.

Last edited by Dan89FLSTC; Jul 10, 2019 at 03:37 PM.

Jul 10, 2019 | 05:12 PM

EVOrider

Thread Starter

Stellar HDF Member

Joined: Feb 2007

Posts: 2,558

Likes: 280

From: Russellville, Arkansas

Cannot get it blow the fuse again......

Disconnected and reconnected a few times.....

Bike is running great and normal operating temperature.

I’m lost.....hard to fix a problem since it just fixed itself so it seems.

I like EFI.....but this is nuts. I’m really leaning towards the carburetor conversion.

Jul 10, 2019 | 05:33 PM

Dan89FLSTC

Seasoned HDF Member

Joined: May 2008

Posts: 21,029

Likes: 12,550

From: South Carolina

Quote:

Originally Posted by EVOrider

I like EFI.....but this is nuts. I’m really leaning towards the carburetor conversion.

It has nothing to do with carburetors or fuel injectors, both type bikes use electricity and wires.

You have a wire somewhere in the ignition circuit that has chafed itself bare and touches ground, it did not fix itself.

You need to get inside the fairing and look for where a harness moves when the bars swing back and forth, look for a section of wire that rubs.

Last edited by Dan89FLSTC; Jul 10, 2019 at 05:39 PM.

Jul 10, 2019 | 05:41 PM

EVOrider

Thread Starter

Stellar HDF Member

Joined: Feb 2007

Posts: 2,558

Likes: 280

From: Russellville, Arkansas

I wish it did fix itself......

Finding that bad wire.....gonna take sometime.

Any ideas which wires could be causing this problem?

Thanks

Jul 10, 2019 | 06:02 PM

Dan89FLSTC

Seasoned HDF Member

Joined: May 2008

Posts: 21,029

Likes: 12,550

From: South Carolina

Come on man, read the post right before yours...

It`s going to take some effort, but once you move those bundles around a bad spot may jump out at you, go for it.

The wire color will be gray before it goes into the kill switch, it will be white/black after the switch all the way to the ignition harness.

Last edited by Dan89FLSTC; Jul 10, 2019 at 06:04 PM.