Normal ohm readings for heated grip circuit?

[John H]

Hey folks,

My heated grips went out, and I saw that the 4 ohm fuse blew. I put an ohm meter across the fuse connections and it read 0, 5.3, and 7.2 ohms from off to high on the heat switch. Do these resistance reading seem normal? I'm trying to figure out if I may have a continuity issue in the wiring (i did notice some of the sheathing cut and some crimps to the wire under the steering column, but nothing else). I popped in another fuse and it seems to be ok, but I'm trying to diagnose if there may be another problem as this is the second time it went out (04 r1150r).

Thanks!!

[NoRRmad]

Well... Zero Ohms indicates a shorted circuit, but that'd blow the fuse as soon as you switched the grips...as you describe it...off. (!)

I assume you mean the 4-AMP fuse, and you're accurately describing the current flow, not the resistance. (The HIGH setting should have the lowest resistance, for instance. Maybe you should make sure you're switched to the proper range of AMPS reading and re-read the results. It goes without saying that 5.3 AMPS will blow a 4-amp fuse.)

[John H]

Thanks for the quick reply...

Yes, is a 4amp fuse.. Pardon my scant electrical troubleshooting knowledge here, btw...

I didn't measure the current. I simply pulled the shorted fuse, attached the leads to my electronic multimeter, turned the bike on, and read the resistance of each switch position. I think you're right, I had my numbers backwards - 5.3 ohms for high, 7.2 for low. I guess if i had a very low ohm reading, that would increase the likelihood of the fuse blowing, (less resistance = more current?). And if i had a frayed wire, the ohms would go up, and if the frayed wire grounded, then the fuse would blow, yes? So I'm trying to figure based on those numbers if I have a continuity problem, a bad connection somewhere, etc. hope my logic is somewhat making sense!!?

Thanks!!

John

[NoRRmad]

I can't really say what you were reading; with the bike on, the battery was pushing current through the circuit, and you were using the multimeter as a fuse. (!) Ohms are measured using the multimeter battery as a current source, and I doubt it puts out the 12 volts that the BMW battery provides. You might get more information by reading the amps through the fuse instead.

But that aside, yes, you could well have frayed, shorted or open wires casued by too-tight zip ties in the area of the steering head. Look for a cut in the sheathing, then slit the rubber, tease the wires apart and examine them closely.

Good luck!

[sweatmark]

The grips seem to fail at either (1) the throttle-side grips wire inside the handlebar (evident if you remove the bar-end weight and peer inside); or (2) within the wiring bundle near front subframe, caused by the previously mentioned too-tight wire ties.

To confirm heated grip wiring status, it's easiest to remove gas tank and measure continuity (resistance) across each grip's connector plug, which is fastened to the front subframe.

Seems that heated grip switches problems are rare, and would require replacement of the RHS handlebar switch module.