| The headlight switch for the 914 is an insanely
expensive item - something near $400 new! Luckily, there seems to be a
fairly good supply of used switches on Ebay. I recently bought a switch, not
because I needed the switch, but because the insert was wrong - it was the
rare, early green fog light insert. I'd wanted this insert, but didn't want
to spent $30 at AA for one! I won the auction and got the switch for $9,
After extracting the insert, I checked out the switch - the
instrument rheostat wire was bent on the end and popped out. I decided to
take the opportunity to see how the switch was made and if it could be
repaired. Based on what I learned, here is a disassembly procedure with some
photos of the internals. Hope this helps out anyone who might need to
rebuild a switch. Note that there are two 914 switches - the "early" skinny
one (the one you see here) and the "fat" late one. I don't know how much the
fat switch differs...
- Remove the knob by unscrewing it from the shaft.
- The contact plate is crimped onto the body of the switch at the
corners. If you have a lot of patience, time, and plenty of small
screwdrivers to break, you can try prying the corners away. Or, you can
take the easy approach and use a Dremel cut-off wheel and simply cut the
corners away. Don't worry about how you'll get the top to stay back on - I
have an ugly but very effective way of doing that in the last step.
- After the contact plate is freed at each corner, it will probably pop
up near the front of the switch. To remove the contact plate without
damaging the switch internals, you will need to hold the rheostat assembly
(at the back of the switch) in place. Hold the switch by putting your
fingers of one hand under the body and your thumb on terminals 58a and
58b. While holding these terminals down, slide the contact plate up over
58a and 58b, remove your thumb and slip the plate off. The rheostat will
stay in the back of the switch. After removing the contact plate, the
switch should look as below (the contact plate is flipped over to reveal
the contact pads):
- It's pretty easy to see how the switch works. The contact slider block
is keyed to the shaft. Each contact slider (there are three) is backed
with small springs to press the slider into the contact plate. The bottom
of the contact slider block has two springs that push plastic pins into
detents in the body to "click" the switch into the three positions. All of
the contact plates seem to be silver plated. The entire assembly is coated
in dielectric grease for lubrication and to prevent arcing. The rheostat
is keyed to the shaft and rotates a contact plate wiper against the
resistance spring. Note that the rheostat assembly is electrically
separate from the switch part.
- OK, let's finish disassembly. Carefully lift off the contact slider
block from the shaft. There are two small springs in the bottom of the
switch that push the plastic pins down - they may fall off into the switch
body. Leave them there until later. Put the slider block aside. Pull the
shaft out of the rheostat, and put it aside.
- If your rheostat is OK, leave it alone! If you need to remove it, be
aware that there are two small springs that will pop it apart if you
simply pull it out without holding it together. The retaining plate is
simply held by shoulders and slots in the switch body. Put your thumb on
it and pull upwards on the terminals - try to hold it together. Once
removed, let the springs move the plate off of the slider and put the
- Below is a picture of the disassembled switch:
- Repair will depend on the problem with your switch. Damaged rheostat
springs can be repaired with careful use of tweezers. Damage to the
sliders can be repaired with good parts from another switch. Damaged
contact plates will need to be replaced with a good part from another
switch. Worn out contact slider block pins can be replaced with good parts
from another switch.
- Reassembly is fairly straightforward. Use contact cleaner and clean
the old grease off of all parts. Coat the bottom of the switch bottom,
spring guides and springs, contact plates, pins, and contact plate with
dielectric grease. Reassemble the rheostat by stacking the retaining
plate, rheostat slider plate, springs, contact slider, and rheostat plate
together and insert the assembly into the switch body (make sure the
retaining plate is oriented so that the tabs at the top limits the
rotation of the rheostat slider plate). Slide the shaft into the switch
body and key it into the rheostat. Reassemble the contact slider plate -
use a good amount of grease on the springs and pins to hold them in place
so that you can slip the slider plate onto the key in the shaft without
the pins falling out into the switch body. Make sure you orient the
contact slider plate as shown in the top photo. Slide the contact plate
back on the top and over the rheostat contacts.
- . If you carefully bent the corners out when you disassembled the
switch, you may be able to bend them back to hold the contact plate in
place - good luck. If you used a cut-off wheel as I suggested, you could
use epoxy to reaffix the contact plate, but you're in trouble if you
should need to disassemble the switch. Instead, use an ugly, but effective
and removable way of holding the plate on - a tie wrap! See the photo
below for where to run it through:
- . You're all done. Use continuity tester or DMM to check the switch
operation before installing. Diagrams of the switch internals are at the
Pelican Parts web site in the
electrical diagrams area.
UPDATE: Regarding the newer "fat"
version of the switch
I've included this image to show the later "fat" headlamp
switch for comparison.
I've wiped off the dielectric grease so you can see the
The only major difference between the "skinny" switch and the "fat" switch
is the contact plate on the left. The "skinny" switch passes all current for
the headlamps and the headlamp lifter relays passed through one
contact(#56). I suspect that all this current causes switch failures, so in
the "fat" switch, current for the headlamps goes through one contact (#56)
and current for the headlamp lifters goes through another contact (#56K).
Note that in the "fat" version, the contact slider on the left is the same
as the two contact sliders on the right. In this picture the contact point
driving the headlights is completely burned off and the contact plate it
touches was rather corroded. I was lucky enough to have a second "skinny"
switch to cannibalize for a good contact slider. If your headlamp contact
point is burned off and you don't have another switch to take a contact
slider from, you can swap the contact slider on the left (headlamps) with
the contact slider on the bottom right. The only functionality you will lose
is the parking light indicator on your dash (note parking light contact in
A few other minor points:
- Since I'm cheap and don't have a Dremel Roto-tool, I used a metal file to
file down the corners to open up the switch instead of prying them with a
screwdriver and it worked fine.
- I got confused by the Haynes manual directions for removing the lamp
switch. It says to follow the directions for the hazard light switch. Those
directions say unscrew the knob AND the shaft. For the headlamp
switch, you can NOT unscrew the shaft (note the scratch marks on the shaft
in the image). Just a heads up.