Keep blowing number 4 fuse on 85 sei

airbats801 · Post by **airbats801** » Sun Dec 02, 2018 4:17 am

I picked up a gl1200 limited the other day with 46k. It seems to run so so. No codes showing, but the dash lcd and function lights arent working. The dash lights all work.

So first thing I did was check fuses, and noticed number 4 dead. I was like well might as well chuck it in, and then I also noticed the trip computer wasnt plugged in. Well, I plugged it in as well. Next thing I know after the new fuse, I had the trip computer smoking. and a blown fuse, before the smoke, the dash did cycle the lights, and the dash was working for a second.

The smoking ended up being a varistor that torched itself. I'm guessing due to a short or a grounding issue.

I looked around the bike, and removed some things, like trailer hitch wiring among other junk, and some random wires. I tested the fuse location with a hot wire, and I feel like it is possible grounding out.

I'm thinking this is going to become a pull the front fairing's off and try to source the issue, but I might as well ask if there is anything else I might check before I have to tear into it this far?

Rednaxs60 · Post by **Rednaxs60** » Sun Dec 02, 2018 9:16 am

Fuse #4 is for the instrument panel, brake light and taillight sensor, and indicator light check relay. If #4 fuse is blowing check these items. If there are add on lights I would check that wiring first. You shouldn't have to take off the front fairing to troubleshoot. Unusual for the trip computer to fail electrically but it happens.

The trip computer is not required for the bike to operate well. It does do one thing for you. If the fuel portion of the trip computer is not giving the necessary readings such as fuel quantity, and distance left to be traveled, it is indicative of the thermistor on the fuel sending unit being U/S. This thermistor can be changed and is fairly easy DIY project. I will look up the thermistor required. I have changed two of these. It is nice to have a working trip computer.

Sounds to me like the PO did some wiring projects and just used the existing wiring and tapped into the lighting wiring.

I would suggest to remove all add on wiring and bring the system back to original, then get the dash going, then address the trip computer issue.

Good luck. Cheers

airbats801 · Post by **airbats801** » Sun Dec 02, 2018 5:09 pm

Thanks, I will look into the tail section. THe harness isn't too bad compared th the 86 sei parts bike I have, but there were a few things, and it's already been modded with the stator plug removal.

Rednaxs60 · Post by **Rednaxs60** » Sun Dec 02, 2018 6:18 pm

Check fuse 7 as well. It is for the travel computer, license plate light, and taillights. If you have an issue with the travel computer wonde rwhy this fuse did not blow as well.

airbats801 · Post by **airbats801** » Sun Dec 02, 2018 7:43 pm

It's possible. I'm going to head out and look at it for a bit right now

airbats801 · Post by **airbats801** » Sun Dec 02, 2018 9:17 pm

been unpolugging everythingm and I it's still blowing, so I pulled the dash, and the bike no longer blows the fuse. I can small something burnt in the dash as well. I'm guessing it has a short.

airbats801 · Post by **airbats801** » Sun Dec 02, 2018 9:43 pm

I pulled the thing apart, and it burned up a varistor, and looks like it took out a transistor or 2 as well.

Rednaxs60 · Post by **Rednaxs60** » Sun Dec 02, 2018 11:07 pm

I've done extensive reading of the various threads and this has got to be a first or if not, close to it. Dash and travel computer unusual combination for both to have an issue. At least you have narrowed the issue(s) so you can now get fixing or replacing. Good luck. Cheers

airbats801 · Post by **airbats801** » Sun Dec 02, 2018 11:53 pm

yeah I agree. I didnt blow the number 7 fuse either. Not sure whats going on. i'd hate to put the spare dash and trip computer in to find out there is some other issue causing the smoking. I suppose if it was a short on the harness side, it would still short unplugged

Rednaxs60 · Post by **Rednaxs60** » Mon Dec 03, 2018 12:11 am

The only route I can suggest is to ensure you unplug any additional wiring that is not original, go back to stock wiring. Is there any additional non-stock lighting up front? Are there driving lights? Disconnect as well.

When you disconnected the trailer wiring, did you remove it in its entirety? Since fuse 4 is for the brake light, possible ground wiring issue. What type of connectors did the PO use, similar to these:

If these were used have a good look at the wiring where these were used, wire(s) could be bare enough to cause a problem.

The stator wiring should not affect the dash or travel computer. Check the regulator/rectifier (RR) plugs near the RR. Shouldn't have any affect on the rest of the electrical system.

Good luck. Cheers

airbats801 · Post by **airbats801** » Mon Dec 03, 2018 1:27 am

Those are my lease favorite plugs in the world lol. I did find one attached to something down under the left cubby. That was removed right away.

So I plugged the new dash in from my 86 sei. It works perfect now, no blown fuses. Go figure. I also plugged my good trip computer and the back lights power up, but it doesnt do anything. I might have something disconnected for all I know, but it's a good start.

I need to look into what causes varistors to fail. I know they degrade with age, but having 2 in seperate devices fail is very odd.

Keep blowing number 4 fuse on 85 sei

Keep blowing number 4 fuse on 85 sei

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Re: Keep blowing number 4 fuse on 85 sei

Re: Keep blowing number 4 fuse on 85 sei

Re: Keep blowing number 4 fuse on 85 sei