Brake switch failure

[Billy56]

I have a 97 FLSTC and I  only put on 1,000 miles since I bought it used.  I've replaced the rear brake switch twice.  I was looking over the maint records and noticed that the previous owner also replaced the switch.  What could be causing this switch to malfunction so often?

Thanks'
Bill

[tinkerman]

Hey Billy,

If the failure symptoms are "no brake light" when you depress the brake pedal vs brake light on all the time or actual observable physical damage to the switch itself then the first thing I would do is make sure that the problem is actually the switch. ie. disconnect the switch from the circuit and check out the continuity of the switch in the on and off position with a muti-tester. If this was becoming a real frustration for me I would likely take the switch off the bike and subject it to some raps and taps and test it several times. It is possible that the switch is OK and you have a intermittant bad connection somewhere between the switch and the lamp or the lamp and ground in the brake light circuit.

If you ultimately conclude that it is the switch then the only guess I can make is that somehow there is too much tension on the switch between the brake lever/pedal and the contact mechanism in the switch which is, with time not allowing it to make contact or conversely there is not enough tension and the switch is not being activated. There is a spring between the pedal lever and the switch right?

Hard to diagnose these things from a distance but those are a couple ideas for what they are worth.

Tinkerman

[JohnS_Rosamond]

I can't give you a better response than Tinkerman, but I agree that unless you're sure that it's the switch, I might suggest that you look at the wires running under the fender to the tail light, or that the wires going to the hydraulic switch are shorting out.  I have not seen a run of bad hydraulic switches for the rear brake.  The one that is more sensitive is usually the front brake light switch.

[gryphon]

If the rear light isn't coming on at all I would pull the two wire from the switch and tough them together. If the light comes on you can be pretty certain it's the switch. If you get a spark then i'd guess you have a ground somewhere. Just to be certain you can run an oms beter between the two posts and hit the pedal. If nothing happens you got a bad switch for sure. Sounds like you've had some bad luck if it is the switch. I have not had the best luck but I usually get at least a few years out of one. The front are another story. they pretty much just suck.

[gryphon]

In my previous post I said "if the rear light isn't coming on at all". I should have said "if the brake light isn't coming on at all".

[ramv102000]

I went through 3 Harley rear brake light switches in about 4000 miles. I tried a Accel switch and no problems for 3000 miles.

     Randy

[Norton Commando]

The "Genuine" HD replacment rear brake light swicth for a '90 FLHS and other models is not fit for purpose, in my mind. The switch I'm refering to is the one that is pressure activated. I couldn't get six months service out of the factory switch , so I replaced mine with a garden-variety Auto-parts-house brake switch: BWD S194. This unit costs only $5 or so and lasts for several years.

[BKACHE]

When was the last time the fluid was changed?
Is any water / crud built up?
Did it stop over the winter when the moisture ladden fluid inside the switch rusted solid in place?

[Norton Commando]

The system was clean and water free; absolutely no rust in the switch. The switches, and I've bought probably six or so of them at the ridiculous price of ~$20 a pop, have failed all year around.

Quite simply the HD switch is just not up to the intended task.

[Evo160K]

I don't use a rear brake light switch, I disconnected it 15 years ago.

That's my preference because I can be slowing down by applying the rear brake pedal (without the rear brake light going on) and at the same time flashing my rear brake light with the front brake lever, to warn the cars behind I'm slowing/stopping.

[Norton Commando]

That's a clever trick there Evo160k.

[lengbyroadking]

What's the part # for the Accel switch? I replaced mine last Spring and noticed this past Fall that the brake light only comes on dim with the rear brake and tends to get brighter when more pressure is applied.

[Evo160K]

Thanks Norton 850, I appreciate that.

[ramv102000]

http://www.jpcycles.com/Search/Search/?Ne=36365&N=274313+4294965978&D1=274313+4294965978&D1=274313&Ntt=&Ntk=&refine=&Ns=image|1||Exact%20Fit|1||CategoryRank|1||TopSeller|1||Universal%20Fit|0&state=

[takwolf]

I did the opposite, dis-connected the front switch so I can slow down in case I have a cop or something behind me.

[spanners]

Had a similar on rear brake light on 95FL Heritage found worn wire inside harness near centre frame post. Stripped soldered and shrink coated and then no problem since.

worth a look maybe?