St1300 -ABS 10A Fuse keeps blowing

[rosara24]

Hi all,

I had a problem with my ST's alternator - it wasn't charging (after checks etc) - so I've replaced it with a second hand unit - with a Guarantee. All seems well except when the ABS light comes on it stays on regardless of what I do. I've checked both 30A fuses and they are okay - I've tried to retrieve any fault codes but the light comes on and refuses to go off - even above 5 or 6 MPH. Latest thing I noticed that the 10 A fuse had blown in fuse box A. When I replaced it and turned on the ignition it just blew again.

Due an MOT soon so it needs fixed before I can get it passed. Anybody got any clues?

Yours Baffled!!

 

[Larry Fine]

Most likely is a pinched wire shorting to ground (engine/frame).

Temporarily wire a 12v bulb in place of the fuse while looking for it. When you find the problem, the light will flicker or go out.

 

[motornut]

Awesome response Larry, use the bikes system as part of the troubleshooting tool. I believe it is a good time to review your install of alternator. It does sound like a coincidence if that popped up at that time.

 

[woodybelle]

My wiring diagram shows forward and rearward fuse boxes and the forward box has 4 10A fuses and the rearward has 2 10A fuses. Fuse A in the forward fuse block provides power to the ABS module and nothing else that I can see. I agree that you probably pinched a wire somewhere and Larry's bulb idea sounds like a great way to troubleshoot it.

 

[Larry Fine]

Awesome response Larry, use the bikes system as part of the troubleshooting tool.

That reminded me about years ago, when setting the ignition timing on my '73 CB750, I temporarily rewired the turn-signal beeper in series with the points, so I could concentrate on watching the timing marks as I rotated the crankshaft.

 

[jfheath]

If it is the ABS fuse that is blowing, check your brake fluid level - make sure that it isn't above the max line. (Yes, really **).

Explanation. If the fluid level is too high (eg perhaps you fitted new pads) then when the ABS tries to cycle to ensure that the pulsing mechanism is in the correct position, it fails, the motor overloads and the fuse blows. No I didn't believe it either, but what you described happened to me after a pad change. A good while before, I had topped up fluid half way through the brake pads' life. When I fitted new pads, there was too much fluid. I blew two fuses before I got round to checking the fluid and drained some out. That cured it.​

​

You won't find this in any manual, and you probably wouldn't think of it. But it is a 2 minute check and costs nothing to fix - if that is what it is.​

 

[Igofar]

What year bike do you have?
If it’s a 02 to 07, and you have the old style ABS ring, remove the three screws and check the ring for cracks.
You won’t see a crack when mounted because the three screws hold it together.
Another thing to check, is see if you have any iron dust/dirt stuck to the magnet.
Do you have a service manual?
The manual will show you how to clear the ABS faults.
You have so many seconds to pull and replace two fuses, and if you don’t time it right, it may take you a couple attempts.
This is just for the ABS issues, check wires and ground issues as well.
Good luck.

 

[rosara24]

It's a 2009 model and I have a service manual. When I remove the fuses it makes no difference as the light doesn't go out after 5 seconds - stays on regardless of what I do. I've just soldered a bulb together with some wire so will need to take tank/airfilter etc off again to check the wiring see if I can find anything.

 

[ST Gui]

Headlight gremlins are often related to a bad ground that can be fixed by running an additional maybe 16ga minimum from the headlight socket's ground wire to a clean solid ground (lol) on the frame. Check the headlight sockets for any signs of corrosion while you're at it. This may or may not be the problem or part of it but it may bite you down the road so check it out while you're looking for a cause.

 

[motornut]

Does sound like a short to positive somewhere. The relay is fused so that should be covered when the fuses are pulled. The jumper with the bulb is best bet for finding it, when you pull fuses are they showing power on both sides of the fuse connections?

 

[rosara24]

Does sound like a short to positive somewhere. The relay is fused so that should be covered when the fuses are pulled. The jumper with the bulb is best bet for finding it, when you pull fuses are they showing power on both sides of the fuse connections?

I've measured the both 30A fuses but there's nothing there. Also when I measure the voltage on the 10A fuse it's the same as the charging voltage at the battery. Flummoxed-so far.... tried the Bulb but couldn't find anything so far. Might have to take the throttle bodies off to see if there's anything underneath that's been damaged.

 

[Igofar]

I wouldn't pull the throttle bodies off, you may damage more stuff trying to do so.
You can see and reach all the electrical stuff without pulling them.

 

[woodybelle]

Fuse A feeds the ABS module without going through any connectors. Fuse A feeds only the ABS module on a red wire. So if you disconnect the ABS module then light across the fuse terminals, with the fuse removed, should be out. If it isn't then you have a short to ground in the red wire somewhere between the fuse block and the module. If the light is out and it still blows fuses with the module attached then then something has gone wrong inside the module as far as I can see. I hope this makes sense to you.

 

[DannoXYZ]

I've measured the both 30A fuses but there's nothing there. Also when I measure the voltage on the 10A fuse it's the same as the charging voltage at the battery. Flummoxed-so far.... tried the Bulb but couldn't find anything so far. Might have to take the throttle bodies off to see if there's anything underneath that's been damaged.

that's not how to measure for shorts. You want to measure resistance-to-ground on output of fuse connector. Similar to finding broken wires. Actual numbers of ohms is more useful indicator than voltage.

For example, you measure voltage at fuse after it's blown. What ya know, there's voltage coming into fuse, but nothing leaving. Doesn't help with finding where short circuit is located.

 

[rosara24]

that's not how to measure for shorts. You want to measure resistance-to-ground on output of fuse connector. Similar to finding broken wires. Actual numbers of ohms is more useful indicator than voltage.

For example, you measure voltage at fuse after it's blown. What ya know, there's voltage coming into fuse, but nothing leaving. Doesn't help with finding where short circuit is located.

Thanks Danno. Food for thought. Will have another look see if things the case.

 

[rosara24]

Fuse A feeds the ABS module without going through any connectors. Fuse A feeds only the ABS module on a red wire. So if you disconnect the ABS module then light across the fuse terminals, with the fuse removed, should be out. If it isn't then you have a short to ground in the red wire somewhere between the fuse block and the module. If the light is out and it still blows fuses with the module attached then then something has gone wrong inside the module as far as I can see. I hope this makes sense to you.

Thanks @woodybelle. The test light goes out when I disconnect the ABS module connector - not the black multi connector but the redish one - the one on the right looking towards the back of the bike.

 

[woodybelle]

The reddish connector is the one that is being fed by fuse A. That plug also has out puts for the rear ABS modulator motor. Check the resistance of the wiring going to the modulator for a short to ground. It may be possible that the motor is shorted too, but I am not sure about this. Maybe Igofar can chime in.

 

[DannoXYZ]

Thanks @woodybelle. The test light goes out when I disconnect the ABS module connector - not the black multi connector but the redish one - the one on the right looking towards the back of the bike.

Ok, this is good progress. Measure resistance-to-ground of fuse-output terminal:

1. measure fuse-output terminal to ground with ABS module plugged in. Ohms = ???

2. measure fuse-output terminal to ground with ABS module unplugged. Ohms = ???

As others mentioned, there may be issue with fluid-level if you've replaced pads recently.

 

[rosara24]

The reddish connector is the one that is being fed by fuse A. That plug also has out puts for the rear ABS modulator motor. Check the resistance of the wiring going to the modulator for a short to ground. It may be possible that the motor is shorted too, but I am not sure about this. Maybe Igofar can chime in.

Ok, this is good progress. Measure resistance-to-ground of fuse-output terminal:

1. measure fuse-output terminal to ground with ABS module plugged in. Ohms = ???

2. measure fuse-output terminal to ground with ABS module unplugged. Ohms = ???

As others mentioned, there may be issue with fluid-level if you've replaced pads recently.

just been out to have a look and the resistance with the module unplugged is Infinity. With it plugged up it starts with a figure but within a few seconds it's 000. I haven't touched the brakes for a while - maybe 6 months since the last set of pads were installed.

 

[rosara24]

just been out to have a look and the resistance with the module unplugged is Infinity. With it plugged up it starts with a figure but within a few seconds it's 000. I haven't touched the brakes for a while - maybe 6 months since the last set of pads were installed.

All sorted. Changed the ABS module and all now working okay. Light goes out as normal at 5/6 MPH and fuse is intact. Many thanks for all the input.....