Triumphrat

Magic1 · 04-13-2008

I have been trying to fix this for the last few weeks now with limited (ok, no) success. Just got the bike recently.
Searched & looked through the forum. Its a 2000 Sprint ST.

My OEM handle bar heaters keep blowing the fuse. This is what I have done in a vain attempt to rectify and what I have found.

- Each side of the handlebar grip pulls 1.5 amps when it is on high (only one grip connected at a time).
- Each grip side works fine (with the fuse intact).
- Noted, the grips are currently connected in parralle.
- I have changed out the relay that allows the heaters to operate only when the ignition is on. I thought that might be where the problem was - nope.
- I have tested the 3 way high,off,low switch with the (high setting) copper and (low setting) resistance wire. Seems to be working fine. But still blows fuses on either setting.

Now the weird bit. It never blows the fuse straight away. It only happens when the motor is running on the road. Cant replicate the the fault in the workshop by wiggling wires. Can't see where any wires could be pinched.

* But if I run just one of the grips (unplug the other one) it runs fine even with a smaller 5amp fuse. Left or right side it doesn't matter. It doesn't blow. Grip gets nice and warm.

But if I try and run both grips, fuse blows within 2 minutes even if I use a 15amp fuse.

Am I missing something? Were the grips supposed to be wired in series?
Or, is it just dodgey wiring that is getting power to ground somewhere only when there is a lot of current going through the circuit (can that happen?)

Anyone have a circuit diagram of where it is all supposed to go?

Sorry if this sounds a bit complex, just thought I would give people something to think about if they were not out riding.

What do you reckon?

airrider03 · 04-13-2008

This may not be an answer, but I'll share it with ya anyway...
A loose battery terminal may blow a fuse. I used to tighten down on the batt. terminals with a phillips screwdriver, being careful not to strip the threads...till one of my fuses (starter) started blowing. Now it's with a socket when cranking down the cables.

What year sprint?

BlewBayou · 04-13-2008

Most common fault is wiring, either an installation error or damage to the wires where they enter the grips.
If you're blowing a 15 amp fuse, I'm surprised that you havent melted a wire somewhere.
Most likely culprit is that it is indeed going to ground somewhere.
I would break the wiring down and give it a 100% inspection from one end to the other. I hate to say this but....If the grips are an integral part of an OEM wiring harness, trace all the grip's wiring back to your power source. This will most likely require unwrapping the wiring harness in places as you go looking for the culprit.

Since you've tried the 15 amp fuse and it has blown as well, I would definately be suspicious of damage to your wiring harness somewhere. Tell tale sign would of course be a burn-thru place on that harness. Probe around under the fairing tracing those wires.

Also, when you run one grip have you tried riding the bike to see if the fuse will blow? Try that and simply alternate grips. Best guess is that one of them is going to ground.

If the bike had the wires unplugged from the switch on the side panel to service the bike you may want to look there to make sure it was re-connected properly and note that from the run end of the switch (the end without the little white symbol) the colours are:
Run end - Dark Brown
Middle - Blue
Start end - Pink
I could not find a schematic anywhere on the web. Certainly a schematic exists out there but I simply could not find one.

Magic1 · 04-13-2008

Thanks for the advice. Its a 2000 model and the weird thing is if I only run one grip (ran each one seperately for a few days commuting to work last week) on a 5 amp fuse it doesnt blow. Both sides pull 1.5amp each (measured). But put them both on and it doesnt last two minutes even with 15 Amp fuse.

Weird.
Thats why I thought that maybe they should be wired in series and the fault is not in the grips?

Grrr... maybe I should just buy aftermarket, install it and be done with it.
From what I have seen on the forum the OEM grips feature a little bit to much in the pain in the butt section.

Magic1 · 05-09-2008

Three weeks on... and the problem has been solved.

I dont understand the why, but the heater wire was intermittantly going to ground between the grip and the handlebar on the throttle side. All I had to do was take the throttle grip off, re insulate the wire, and hey presto. No more problems.

I dont understand why the throttle side wouldnt blow the fuse on its own, I can only assume that it was the infrequent earthing through engine vibration coupled with the extra 1.5amp of the other grip that kept blowing the fuse. The vibration was not enough on its own. I dont know. But its fixed. So if anyone has similar symptoms with the OEM heated grips. I hope this works for you.

I feel so smug on cold mornings now

Cheers
Matt

cricket1 · 05-09-2008

Quote:

Originally Posted by Magic1

I feel so smug on cold mornings now

Cheers
Matt

Great to hear you got it fixed!

It's getting warmer here, and I am using the heated grips less. What's up with cold mornings??

Oh yeah, that's right, you Aussies and Kiwis are headed into winter.