2004 Sportster guages fuse blowing

[JLew]

Good day,

I have a 2004 Sportster with the 155 4-Tec which my wife and I love. Problem - the guages fuse (located in the engine compartment MPEM fuse cluster) keeps blowing. This knocks out all the guages, beeper, and warning lights. The engine still runs fine. It is somewhat intermittant as it may work for a couple hours without blowing, and then next time I will blow three fuses in a row. All guages work except for speedometer (which I believe is a seperate issue). The fuel guage is inaccurate but still works (at half full I have to head for shore because it really means empty!). Otherwise everything else on the boat works great!!

I have read the shop manual and spent countless hours thinking about this problem. Does anyone happen to know what this problem may be? Is it a faulty guage grounding out? Is it a faulty sending unit? Or is it something inside the MPEM itself?

What would be intermittantly drawing such high amperage to blow this 2A fuse? I even upped it to a 5A and it still does the same thing.

Thanks for your time, J.

 

[Dr Honda]

It's not a "Known" issue of any kind... so I'm going to say... you either have a short in the wires, or in a gauge.


I would start with physically looking at the wires. Anywhere they are "Zip tied" up... or they pass a control (like by the steering, or throttle) look for a rub.


If they are OK... I would disconnected all the gauges, and go for a ride. After an hour, or so... check the fuse. If it's still good... plug in ONE gauge, and go for another ride. Since the speedo has a known issue... plug that back in last.


Intermittent issues can be a pain in the butt. So, all you can do, is systematically go though each step until you find it.

 

[byebye]

Did you ever find out what was wrong with your speedometer? All my gauges work EXCEPT for the speedometer. Possibly a fuse issue?

 

[JLew]

Thanks Dr Honda for the advice. I will try that procedure - sounds like a good plan. I am glad to hear it's not a "known" issue - I think. I hope its that speedometer guage since its not working anyway. I just can't understand what else it would be other than the electronic interface box itself (which looks expensive) - I pulled the connectors and all looks clean and new.

With regards to byebye's post about the speedometer - to be honest I haven't troubleshooted that yet. I was hoping to get the guages to be working reliably before I look into it. I have read that there is a test procedure for the sending unit (on hull at stern) using an ohm meter. I will likely start there and if that's working it has to be the guage itself. If I am really lucky the speedometer guage will be the source of both my problems! It won't be a fuse issue if your other guages are working fine - there is only 1 x 2A fuse running all guages from what I have learned. How is your fuel guage working? Does it read fairly accurately (ie: from FULL all the way down to EMPTY)?

 

[byebye]

The internet consensus on the speedometer seems to be let it fail - GPS speed is far more accurate. My pinwheel turns well, at some point I may check the wires coming off it but I'm not going to knock myself out over it.