Debugging Grip Heaters

[maduko]

I found some very helpful posts on heated grips searching the forum. Just pulled the tank and got out the multimeter to try and fix them. But my trouble, as usual, appears to be unique. Any suggestions would be appreciated.

I've got no heat at all. The fuse is good and I have a strong 12 volts at the fuseblock when the key is on. I checked the wiring along the handlebars and the infamous tiewrap appears to have been removed as per the recall. I removed another one next to the right-hand controls that seemed tight. I also checked where the right grip heater wire runs into the handlebar and it doesn't appear to be chafing on the hole.

So, the tank comes off at this point. I was hoping to find them unplugged, but no such luck.

First I checked the resistance between the plug and the grips. Both show about 8.9 ohms on the 2k scale. That seemed to agree with what I'd read somewhere and eliminated the broken wire theory.

Next I checked voltage with the heat switch turned on and got 12+ volts.

Finally I reconnected the plug and checked voltage across the connector and I only see 8.4 volts on either side. That indicates to me only 4 volts are making it to the grips.

If that's the case am I looking at a faulty switch? Have I overlooked something simple?

[maduko]

Okay, let me rephrase that....

Anyone now how the grips and switch are wired?

[NoRRmad]

I think the grips have a center tap. Low setting runs current from one end of the grip to the other. High setting runs from the center tap to each end, seeing half the ohms, resulting in twice the amps.

(Boy, the Clymer manual has zip on this... But I think I saw a diagram once that detailed the center tap. Equally possible I suppose is that the grips run in parallel on high, in series on low settings.)

CycleRob?

[CycleRob]

I have a BMW wiring diagram somewhere and it may be necessary to determine what grip wires to connect to for tests if you can't logically determine that with the Ohmmeter.

Multimeters are great for troubleshooting, but the voltage reading they give you may be misleading depending on the power draw. Think of a car with a corroded battery terminal connection. The dome lite works and the radio plays, but as soon as you try the starter, everything goes dead. It's the same with his low power draw multimeter reading 12V at the grip terminal plug-in. The grips are a higher current draw and a poor power connection somewhere isn't transferring the full amps needed.

Check the Ohmmeter reading while turning the bars and twisting the throttle. It should read the same. It could be a fuzzy switch terminal or even a broken neck harness wire where 95% of the strands are broken. The best way is to load test the grip power source with a brakelite bulb. I normally use a headlite Halogen bulb, but they draw just over 4 Amps and that would blow the 4 Amp grip fuse! Solder 2 wires to the signal/brake bulb and hold the wires in place inside the grip power plug. Key & grip switch on, it should illuminate brightly. If it's very dim or dark, just keep moving/flexing ALL the suspect wires/plugins and cycling the switch On/Lo/Hi/Lo/Off 30+ times. When it flickers and/or gets bright, you found it!

[maduko]

I checked the resistance again while moving the steering around. No change in the ohms at all. Haven't tried load testing it yet- but if it's dropping 8 volts that pretty much tells me there's a problem.

Then I looked into the switch a little closer. I can't figure out how to get it out of the plastic housing to access the connections on the back.

But I did find an open circuit. With the switch on high or low I have continuity between the green (supply) wire and the orange. But nothing between the green and black wire in either setting.

[maduko]

Anyone ever dismantled one of these right side switches?

I've got the tiny screw off and the thing comes halfway apart but something appears to still be holding it.

[Henzilla]

I recall 3 screws total. one under the housing, one at end by grip, and maybe one from the front side And the silly question, is the mirror off? I had to mess with an 02 to free the housing.

[maduko]

I recall 3 screws total.

I'm waaay past that. The switch is off and dangling by the wires. I'm trying to get the pretty plastic cover off the business end of the switch. It doesn't appear to be a "user serviceable part."

[baltm604]

I have not done this to the right side switches, but on the left side........

There is one regular screw and two security screws on the underside or back of the switch housing. I carefully drilled out the two security screws, loosened the third, and it came apart. There might be a sticker covering the security screws you may have to peel off first, I can't remember for sure.



Bill

[Klockwerken]

Funny that this subject is coming up...just last night, I noticed that my left grip is not heating at all. The right side is toasty warm but the left side is kaput as they say in German.

Now what do I do, Ollie? Hopefully it si a cheap and easy repair similar to my headlight connector that CycleRob & Company were kind enough to help me through awhile ago.

It's getting colder in Cleveland, Ohio lately, don't cha' know!

[maduko]

I tore up the plastic "cover" getting the switch apart. The good news is the bike is back together and everything works. The plastic is cracked and ugly but I'll live.

Turns out I had a one broken wire, two about to break and one wire pulling the switch contact out of socket. The grip heaters were merely a warning of many failures to come!

I guess the wiring loom recall was done late in life?

The right hand switch has one torx screw and a VERY tight snap-in pin holding it together. In theory it should unsnap after removing the screw. Yeah.. well, it don't.

[maduko]

Funny that this subject is coming up...just last night, I noticed that my left grip is not heating at all. The right side is toasty warm but the left side is kaput as they say in German.

Get your ohmmeter after the brown/black wires in the connector under the tank. You'll probably find one of them has no continuity. Start peeling zip ties!

[Klockwerken]

So the heating element is most likely good still and it's a matter of continuity? Hmmm...I will consult by electrician friend.

I am good with mechanics but electrical???

Thanks.

[SLEDGE]

I have a proble with my rt heated grip not heating. I checked it out with a test light last night and had power to the heating element.I then checked the element wires and the test light lit. the light was bright in the high position and dim in the low position. It would seem to me that the element wires are in tact and should heat, they are cold. The left side heats fine. what I am I missing?

[maduko]

How did you connect the test lamp?

I would unplug the connector where the brown and black wires from the grips plug in and connect an ohmmeter. My guess is you'll have zilch on the RH side. You should see about 9 ohms on each side.

Look over the wiring loom coming from the RH combi switch. The zip tie closest to the switchgear and the one near the steering head are the most common culprits.

[SLEDGE]

I must be working too hard that would not test for an open. I would have to disconect it. I must have an open will have to fix it or spinned $58.00. Thanks

[maduko]

I must be working too hard that would not test for an open.

Right.

I'd almost bet it's at one of those two spots. If you haven't pulled the tank off yet you might feel around on the harness. Slice the wrapper in those spots and you'll probably find your break. The wires for the heaters run separate of the main wiring loom.

[SLEDGE]

I found it! Burnt & broken wire in the heating element.I had to peel back the hand grep and remove the brown factory insulation.Found it 60mm from the switch. I soldered a jumper across the open circut and now I have heat.
I thought I had nothing to loose and I saved$58.00.

The gods of the heated grips were smiling on me.