Brake light switch

[Zack1978]

Hi everyone,
The brake lights have stopped working on my 72 coupe, and for safety sake I need to fix the lights. It would seem that the culprit could be the brake light switch. Do the switches fail often, or are they generally a never fail item? The switch is screwed into the master cyl, correct? Can I swap the switch without bleeding the brake system?
Also it seems that there are two and three prong switches, which switch will my car most likely have?

Thanks,
Zack
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1972 Coupe

[Eric&Barb]

Good quality ones last just about forever, low quality ones you should buy a few dozen of....

Depends how much your VW is stock or screwed up by who knows how many DPOs. Turn steering to full right and take a peek at the MC inside of the left tire to sort it out.
_________________
In Stereo, Where Available!

[butlern]

you will have the 3-prong.

Easy to swap without bleeding, but you have to be ready to pull the old and thread in the new quickly/immediately, or you will lose fluid. Make sure you have rags and gloves to protect you and the pan.

Previous comment about quality is spot on. I have had several new in the box that were bad (Chinese/Brazilian), so try to get your hand on a real Hella units.

Replace both. They are relatively inexpensive.

Good luck!

Noah

[Zack1978]

Ok so I had a chance to look under my car today at the master cylinder. It seems that my problem is as simple as the wires fell off the brake light switch.
But here is the question: I have a three prong switch, but it seems that only two wires were actually connected. On the harness there are three wires, but one of the three is cut very short with no spade connector on it. The other two wires have spade connectors attached, so they appear easy to reattach. Can the system work with only two wires attached (kinda of a rhetorical question, because I assume it did work with only two wires)? What is the third wire for? Also is there a correct and incorrect way to hook up the two wires? Do I just try it both ways until the lights work?
Also in another post it mentions two brake light switches? Are there really two?

Thanks,
Zack
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1972 Coupe

[Eric&Barb]

Stock for all post-1966 VWs should have two senders. You need all three wires on each brake sender so the brake failure warning light will work when, not if, you have the front or rear brake circuit fail.

Learn how to solder and heat shrink a new brass terminal and a little bit of new wire to get that last connection working. Find the second sender, or if you have one or two hose connections between the brake fluid reservoir and MC.
_________________
In Stereo, Where Available!

[Zack1978]

[kreemoweet]

Some (cheaper) replacement M/C's only have provision for one switch. It's likely a PO opted to go the cheap route, and
cut off the wire going to the warning light, since it would then be nonfunctional. There should be the remains of the second
set of wires going to the missing second switch somewhere down there, but who knows what the PO did. If you ever need to
replace your current switch, a 2-prong switch would be more appropriate.
_________________
'67 bug: seized by the authorities
'68 bug: seized by the authorities
'71 kombi: not yet seized by the authorities

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[Zack1978]

Ok so I played with the wires today, and nothing worked. There are three wires from harness. At first I thought that only two wires were connected, but perhaps all three were since I found a broken spade connector just below the master. I also can't find where a second brake switch would be?
The wiring diagram is not much help, since it does not show which prong each wire should go on. Can the brakes work with only two wires connected to a three prong switch?


Thanks,
Zack
_________________
1972 Coupe

[kreemoweet]

The second stock switch would be on the M/C. The Gallery on this site is full of photos of M/C's with two switches, and there are thousands more
on Google image search. Like I said, your M/C appears to have only one. The connection diagram for the brake light switches is in the Brakes and Wheels
chapter of your Bentley service manual. Since the red wire to the warning light is useless with only one switch, you have only two wires to contend with.
And yes, the brake lights will work. That's assuming the switch itself is still working, but cheap brake light switches are notorious for failing early, and the PO sounds
like the sort of chap who would cheap out anywhere he could.
_________________
'67 bug: seized by the authorities
'68 bug: seized by the authorities
'71 kombi: not yet seized by the authorities

Stop dead photo links! Post your photos to The Samba Gallery!

[swavananda]

This should help you on the wiring:

http://www.speedyjim.net/schem/3brake.gif

[akear]

New Question... I have a '70 with the dual, three-prong switches, and no brake lights. To test the switch I jumped the terminals on one of the switch connectors and the lights lit up. If I'm reading the wiring diagram correctly, either switch should energize the lights, so I have two bad switches, correct?

[Eric&Barb]

[swavananda]

[jbassman]

I also installed Keith`s electric brake light switch, and it works great.
After having direct replacement Hella switches fail after 3 years, I needed something more reliable.

This is not a paid endorsement.